SALE AND PURCHASE AGREEMENT

Exodus Communications K.K. ("Purchaser"), The Nomura Real Estate Development
Co., Ltd. ("NRE") and Nomura Research Institute, Ltd. ("NRI") entered into this
Sale and Purchase Agreement as of April 25, 2000 (this "Agreement") regarding
the sale and purchase of real estate etc. under which Purchaser is the purchaser
and NRE and NRI are the sellers on April 25, 2000 as follows.

Article 1
(Definitions)
In this Agreement, each term in the following subparagraphs shall have the
meaning as defined below. 
    1.  "Land" shall mean the land specified in the Land Schedule attached
        hereto.
    2.  "Building" shall mean the building specified in the Building Schedule
        attached hereto. The Building includes the Equipment/Fixtures I.
    3.  "Equipment/Fixtures I" shall mean the equipment and fixtures owned by
        NRE specified in the Equipment/Fixtures Schedule attached hereto.
    4.  "Equipment/Fixtures II" shall mean the equipment and fixtures owned by
        NRI specified in the Equipment/Fixtures Schedule attached hereto.
    5.  "Property" shall mean the Land, the Building and the Equipment/Fixtures
        II, collectively.
    6.  "Exodus" shall collectively mean Purchaser, Exodus Communications Inc.,
        or their directors, officers, employees, working staffs, agents,
        contractors, service consignees and other relevant persons.
    7.  The "Memorandum of Agreement Regarding Sublease" shall mean the
        Memorandum of Agreement Regarding Sublease dated February 24, 2000
        entered into among Exodus Communications K.K., NRE and NRI.
    8.  The "Office Space Sublease Agreement" shall mean the office space
        sublease agreement regarding Nomura Fudosan Shinjuku Building as of
        February 24, 2000 entered into between Exodus Communications K.K. and
        NRI.

Article 2.
(Sale and Purchase between Purchaser and NRE)
1.  NRE shall sell to the Purchaser, and the Purchaser shall purchase from NRE,
    the Land and the Building, in accordance with this Agreement.
2.  The purchase price in the preceding paragraph shall be 5,544,319,200 yen.
    The details of the purchase price shall be as follows.
    1.  The Land:  4,842,516,000 yen
    2.  The Building: 668,384,000 yen and the consumption tax of 33,419,200 yen
<PAGE>
 
3.  The Purchaser and NRE hereby confirm that the consumption tax in the
    preceding paragraph is calculated on the basis that the consumption tax rate
    (i.e., the total of the tax rates under the Consumption Tax Law and the
    Local Consumption Tax Law) effective as of the execution date hereof is 5%,
    and they agree that the amount of the consumption tax in the preceding
    paragraph will automatically change as a result of any change in the tax
    rate applicable to the sale and purchase hereunder after the execution date
    hereof.
4.  Should any new tax similar to the consumption tax be imposed on this
    Agreement due to a change in the tax system after the execution date hereof,
    the Purchaser shall bear the burden of such tax.

Article 3.
(Sale and Purchase between Purchaser and NRI)
1.  NRI shall sell to the Purchaser, and the Purchaser shall purchase from NRI,
    the Equipment/Fixtures II, in accordance with this Agreement.
2.  The purchase price in the preceding paragraph shall be 828,555,000 yen
    (which consists of the Equipment/Fixtures II of 789,100,000 yen and the
    consumption tax of 39,455,000 yen).
3.  The Purchaser and NRI hereby confirm that the consumption tax in the
    preceding paragraph is calculated on the basis that the consumption tax rate
    (i.e., the total of the tax rates under the Consumption Tax Law and the
    Local Consumption Tax Law) effective as of the execution date hereof is 5%,
    and they agree that the amount of the consumption tax in the preceding
    paragraph will automatically change as a result of any change in the tax
    rate applicable to the sale and purchase hereunder after the execution date
    hereof.
4.  Should any new tax similar to the consumption tax be imposed on this
    Agreement due to a change in the tax system after the execution date hereof,
    the Purchaser shall bear the burden of such tax.

Article 4.
(Payment Date and Payment Method)
1.  The Purchaser shall pay NRE 554,481,920 yen in total of the purchase price
    as set forth in Article 2, representing 551,090,000 yen plus 3,341,920 yen
    as consumption tax on the taxable portion thereof upon the execution of this
    Agreement and shall, subject to Paragraph 2 of Article 12, pay NRE the
    remaining balance of the purchase price no later than March 31, 2001, by
    wire transferring each amount to the bank deposit account designated by NRE
    (any wire transfer charges shall be borne by the Purchaser). Transfer of
    ownership of the Land of and the Building shall occur as set forth in
    Paragraph 1 of Article 13.
2.  The Purchaser shall pay NRI 82,855,500 yen in total of the purchase price as
    set forth in Article 3 upon the execution of this Agreement and shall,
    subject to Paragraph 3 of Article 12, pay NRI the remaining balance of the
    purchase price no later than March 31, 2001, by wire transferring each
    amount to the bank deposit account designated by NRI (any transfer charges
    shall be borne by the Purchaser). Transfer of ownership of the
    Equipment/Fixtures II shall occur as set forth in Paragraph 2 of Article 13.
<PAGE>
 
3.  The "remaining balance" shall mean an amount calculated after applying by
    Articles 2.3, 2.4, 3.3 and 3.4. 
4.  With respect to the acceptances of the purchase prices in the preceding two
    paragraphs, NRE and NRI shall deem the wire transfer receipts issued to the
    Purchaser by the bank(s) as the receipts and will not issue any receipt to
    the Purchaser. The Purchaser shall not object to this treatment.
5.  NRE shall take any measures as specified in Subparagraph 1 of Paragraph 1 of
    Article 41, referred to by Paragraph 1 of Article 41-2 of the Building Lots
    and Buildings Transaction Business Law (Guarantee Entrustment Agreement with
    a Real Estate Guaranty Co., Ltd.) with respect to the amounts received from
    the Purchase upon the execution of this Agreement.

Article 5.
(Change of the Subject of Sale and Purchase)
1.  If any portion of the Building or the Equipment/Fixtures II is removed due
    to construction or other work which Exodus itself or NRE, NRI or any third
    party, with Exodus' prior approval, conducts during the period from the
    execution hereof to the delivery of the Property, the removal portion shall
    automatically be excluded from the subject of this Agreement.
2.  The purchase price hereof shall not be changed even in the event of the
    preceding paragraph.

Article 6.
(Repairs by NRE and NRI)
1.  In the event that there occur any defect, deficiency, abnormality,
    malfunction, or suspension of operation etc. with respect to the Property
    until the time of the delivery of the Property to the Purchaser, NRE and NRI
    shall have a necessary and reasonable duty of repair therefor, in accordance
    with their respective ownership portions of the Property, and shall have no
    duty of compensatory damages, duty to renovate equipment/fixtures, duty of
    increase utility or functionality thereof, nor any other duty to the
    Purchaser regardless of any reason whatsoever. Such repair obligation shall
    not extend to the improvements or equipment/fixtures installed or added by
    the Purchaser.
2.  NRE or NRI shall bear the expenses for performing repair works as set forth
    in the preceding paragraph; however, if the Purchaser deems repair works
    beyond the scope of those set forth in the preceding paragraph necessary,
    the Purchaser shall make a prior consultation with NRI and NRE, and if the
    parties reach an agreement as to such repair works, the Purchaser shall be
    responsible for any amount exceeding the scope of the repair works set forth
    in the preceding paragraph, and perform such repair works.
<PAGE>
3.  Notwithstanding the provision of Paragraph 1, if it is expressly required by
    law, ordinances or the orders of the relevant agencies, for the Property to
    be repaired, altered or equipment installed immediately without any grace
    period, NRI or NRE, as the case may be, shall conduct such repair,
    alteration or installation work at its responsibility and expense, in
    accordance with their respective ownership portions of the Property;
    provided, however, that if such request is related to the portion subject to
    the construction work which the Purchaser will conduct or has conducted
    under the preceding Article, the Purchaser shall, in its responsibility and
    expense, perform the repair, alteration or installation work so requested.

Article 7.
(Sale and Purchase based on Public Register)
The subject area for this sale and purchase transaction of the Land and the
Building shall be based on the area set forth in the real estate registry. Even
if there were any difference between the actual area and the area in the real
estate registry, the Purchaser, NRE and NRI shall not make any claim or
objection such as a claim to increase or decrease the purchase price, against
one another.

Article 8.
(Transfer Registration of Ownership)
1.  NRE and the Purchaser shall apply for the transfer registration of the
    ownership for the Land and the Building no later than March 31, 2001.
2.  The fees and expenses required for the transfer registration under the
    preceding paragraph (including, but not limited to, any registration tax,
    stamp duty, and fees for a judicial scrivener) shall be borne by the
    Purchaser.

Article 9.
(Delivery)
1.  NRE and NRI shall deliver their respective subject of the sale and purchase
    to the Purchaser on an as-is basis, no later than March 31, 2001.
2.  With respect to the delivery under the preceding paragraph, the delivery of
    the portion possessed by Exodus shall be made by the method of "summary
    delivery (kanni-no-hikiwatashi)" provided for in Paragraph 2 of Article 182
    of the Civil Code or the method of "transfer of possession by direction
    (sasizu-ni-yoru-senyuiten)" provided for in Article 184 of the Civil Code,
    and the delivery of the other portion shall be made by the method of "actual
    delivery" provided for in Paragraph 1 of Article 182 of the Civil Code. If
    there is a portion possessed by NRI, the delivery by NRE shall be made by
    the method of "transfer of possession by direction" provided for in Article
    184 of the Civil Code, and the delivery by NRI shall be made by the method
    of "possession recharacterization (senyu-kaitei)" provided for in Article
    183 of the Civil Code.
3.  The Purchaser, NRE and NRI shall, by the time of delivery of the Property,
    check and confirm the condition of the Land and the Building (excluding the
    Equipment/Fixtures I) and the operative condition of the Equipment/Fixtures
    I and the Equipment/Fixtures II in the presence of the three, and shall,
    upon the time of delivery of the Property, exchange and deliver the results
    thereof in writing to one another.
<PAGE>
 
Article 10.
(Removal of Encumbrances)
1.  No later than March 31, 2001, NRE and NRI shall remove or deregister any
    restrictions or encumbrances such as any security interests including any
    mortgage, maximal-hypothec, pledge and assignment-type mortgage, and any
    usufructuary rights including superficies and lease, and any provisional
    attachment, provisional disposition and any other limitation or burden which
    would prevent the Purchaser from exercising its entire ownership-rights in
    the Property, whatever the name or form may be. Provided that the foregoing
    shall not apply to the possession by Exodus and the possession by NRI
    pursuant to its agreement with the Purchaser.
2.  NRE and NRI shall, no later than March 31, 2001, remove the Heat Exchangers
    No. 1 and No. 2 owned by NRE and a portion of CPU battery equipment (CVCF
    rectifier 10 through 12, CVCF recharger 10 through 12, CVCF rectifier for
    control and CVCF recharger for control), at its responsibility and expense,
    in accordance with their respective ownership portions of the Property. The
    Purchaser shall cooperate in NRE's and NRI's activity for such removal, if
    necessary.

Article 11.
(Delivery of Document, Key, etc.)
1.  NRE shall deliver to the Purchaser the documents specified in Document
    Schedule I attached hereto and key etc. separately agreed upon between the
    Purchaser and NRE, no later than March 31, 2001.
2.  NRI shall deliver to the Purchaser the documents specified in Document
    Schedule II attached hereto and key etc. separately agreed upon between the
    Purchaser and NRI, no later than March 31, 2001.
3.  Paragraph 2 of Article 9 shall apply mutatis mutandis to the delivery under
                                         ----------------
    the preceding two paragraphs.

Article 12.
(Simultaneous Performance, Etc.)
1.  NRE's and NRI's respective repair obligations under Paragraph 1 of Article 6
    and removal obligations under Paragraph 2 of Article 10 shall be performed
    prior to Purchaser's payment obligations under each paragraph of Article 2,
    each paragraph of Article 3 and Paragraphs 1 and 2 of Article 4 and
    settlement obligations under the proviso of Paragraph 2 of Article 15.
2.  NRE's obligations under Paragraph 1 of Article 8, each paragraph of Article
    9, Paragraph 1 of Article 10, Paragraph 1 of Article 11 and the proviso of
    Paragraph 2 of Article 15 shall be performed simultaneously with Purchaser's
    payment obligations under each paragraph of Article 2 and Paragraph 1 of
    Article 4 and settlement obligations under the proviso of Paragraph 2 of
    Article 15.
3.  NRI's obligations under each paragraph of Article 9, Paragraph 1 of Article
    10, Paragraph 2 of Article 11 and the proviso of Paragraph 2 of Article 15
    shall be performed simultaneously with Purchaser's payment obligations under
    each paragraph of Article 3 and Paragraph 2 of Article 4 and settlement
    obligations under the proviso of Paragraph 2 of Article 15.
<PAGE>
 
4.  By the agreement among the Purchaser, NRE and NRI, the due date of the
    performance of the obligations under the preceding two paragraphs may be
    accelerated to any date coming on or after June 1, 2000.

ARTICLE 13.
(Transfer of Ownership)
1.  The ownership of the Land and Building shall be transferred from NRE to the
    Purchaser when the Purchaser has fully paid to NRE and NRE has received from
    the Purchaser, the purchase price thereof as set forth in Article 2;
    provided, however, that in the event that the Purchaser has fully paid the
    purchase price as set forth in Article 2 on any date earlier than the due
    date set forth in Paragraph 1 of Article 4, NRE shall be entitled to reject
    the delivery of, and hold in its possession, the Land and Building
    gratuitously until the deadline of delivery as set forth in Paragraph 1 of
    Article 9, except for the cases where the parties reach agreement under
    Paragraph 4 of Article 12.
2.  The ownership of the Equipment/Fixtures II shall be transferred from NRI to
    the Purchaser when the Purchaser has fully paid to NRI and NRI has received
    from the Purchaser, the purchase price thereof as set forth in Article 3;
    provided, however, that in the event that the Purchaser has fully paid the
    purchase price as set forth in Article 3 on any date earlier than the due
    date set forth in Paragraph 2 of Article 4, NRI shall be entitled to reject
    the delivery of, and hold in its possession, the Equipment/Fixtures II
    gratuitously until the deadline of delivery as set forth in Paragraph 1 of
    Article 9, except for the cases where the parties reach agreement under
    Paragraph 4 of Article 12.


ARTICLE 14.
(Boundary)
1.  The Purchaser and NRE confirm that NRE has clearly indicated to the
    Purchaser the boundary between the Land and the adjoining land (which does
    not mean the boundary confirmed with owner of the adjoining land) by a
    boundary stone by the execution of this Agreement.
2.  NRE shall not take any responsibility regarding the boundary clearly
    indicated under the preceding paragraph, even if any dispute arises in the
    future with respect to such boundary between the Purchaser and the owner of
    the adjoining land and/or the boundary is found to be false.
3.  NRE shall not be responsible for making a survey regarding the Land.
<PAGE>
 
ARTICLE 15.
(Allocation of Taxes and Other Public Charges)
1.  With respect to taxes, other public charges and expenses for gas, water
    supply, electricity and any other expenses or duties, those expenses or
    duties arising on or before the immediately proceeding day of the delivery
    date shall be borne by NRE and NRI and those arising on and after the
    delivery date shall be borne by the Purchaser; provided, however, that if
    NRI holds the Building in its possession after the delivery date, the
    parties method and other terms of burdening the above charges and expenses
    shall be set forth in the lease agreement between the Purchaser and NRI. The
    initial date to count the fixed assets tax and city planning tax shall be
    January 1.
2.  Settlement under the preceding paragraph (including payment of consumption
    tax incidental to such settlement, to be paid from the Purchaser to NRE and
    NRI) shall upon determination of the actual amount to be paid, be made among
    the Purchaser. NRE and NRI without delay; provided, however, that if there
    is any actual amount which has been determined until the time of performance
    by the Purchaser, NRE and NRE of their respective obligations under Article
    12, settlement shall be made for such actual amount, simultaneously with the
    said performance of such obligations.
3.  The real estate acquisition tax imposed on the acquisition of the Property
    shall be borne by the Purchaser.

ARTICLE 16
(Due Diligence)
1.  The Purchaser hereby confirms and represents to NRE and NRI without
    objection that:
    (1)  The Purchaser has conducted adequate research on the Property with
         respect to, including, without limitation, its current condition,
         operating condition, repair history, and durability, by the on-the-spot
         confirmation, geological survey or other methods, with the cooperation
         of NRE and NRI, taking advice of the experts employed by the Purchaser
         prior to the execution of this Agreement;
    (2)  The Purchaser has received adequate explanation prior to the execution
         of this Agreement from NRE and NRI pursuant to the Outline of
         Equipment/Fixtures attached hereto or otherwise that the Building and
         the Equipment/Fixtures II show phenomena resulting from deterioration
         caused by the lapse of time or natural wear and tear, and that dirt,
         damage, destruction, malfunction, abnormality, failure, erratic
         operation or the like due to such deterioration and wear and tear are
         likely to occur; 
    (3)  NRE and NRI have disclosed to the Purchaser the documents set forth in
         the Disclosure Document Schedule attached hereto, and the Purchaser has
         perused and fully understood the contents thereof prior to the
         execution of this Agreement;
    (4)  The Purchaser enters into this Agreement after having taken the result
         of the above subparagraphs into consideration.
<PAGE>
 
2.  NRE and NRI shall not be responsible for any obligations or liability,
    regardless of the cause of claim such as warranty of no-latent defects,
    arising out of or in connection with the defects which the Purchaser is or
    could have been aware of as a result of the survey etc. under each
    subparagraph of the preceding paragraph.

ARTICLE 17
(Treatment of Warranty of No Latent Defects regarding the Land and Building)
1.  NRE shall be responsible to the Purchaser for latent defects in the Land and
    the Building only for the period of two (2) years form the date of delivery.
2.  The Purchaser and NRE hereby confirm without objection that dirt, damage,
    destruction, malfunction, failure, erratic operation or the like which is
    attributable to deterioration by the lapse of time or natural wear and tear
    shall not be included in the defects under the preceding paragraph.
3.  NRE shall bear no responsibility, regardless of the cause of claim such as
    warranty of no-latent defects, to the Purchaser for the dirt, damage,
    destruction, malfunction, abnormality, failure, erratic operation, or the
    like of the Property resulting from or in connection with construction by
    Exodus to add, improve, or renew the equipment/fixtures in accordance with
    the Memorandum of Agreement Regarding Sublease before the delivery of the
    Land and the Building.

ARTICLE 18
(Exemption from Warranty of No-Latent Defects regarding Equipment/Fixtures II)
NRI shall have no obligation, regardless of the cause of claim such as warranty
of no-latent defects, default, responsibility in contract or tort, or
responsibility for unjust enrichment, against the Purchaser for any damages
whatsoever with respect to dirt, damage, malfunctions, abnormality, failure,
erratic operation, or the like of the Equipment/Fixtures II.

ARTICLE 19
(Loss before Delivery, etc.)
1.  If all or a substantial part of the Property is damaged or lost due to force
    majeure or any other causes not attributable to either the Purchaser, NRE, or
    NRI before the delivery of the Property, and the purpose of this Agreement
    becomes impossible to achieve, the Purchaser may, by notifying NRE and NRI
    in writing within one (1) month after the date of such damage or loss, elect
    to either (i) terminate this Agreement, or (ii) perform this Agreement. NRE
    and NRI may terminate this Agreement by notifying the Purchaser in writing
    thereof under the joint names, only if the Purchaser fails to make such
    election. For the purpose of this paragraph, "a substantial part of the
    Property is damaged or lost" shall mean the cases where the expenses
    necessary for repairing such damaged or lost portions exceed 5% of the total
    amount of the purchase price of the Property under Articles 2 and 3.
<PAGE>

2.  In the event of termination of this Agreement under the preceding paragraph,
    NRE and NRI shall immediately reimburse any money received from the
    Purchaser without interest upon termination of this Agreement. Articles 21
    through 24 shall not apply to any case where the damage or loss of the
    Property amounts to the degree set forth in the preceding paragraph.
3.  If the Purchaser elects to perform this Agreement under Paragraph 1, the
    Purchaser, NRE and NRI shall use their respective efforts to accelerate the
    due date of the performance of their respective obligations to any date
    coming on or after June 1, 2000, pursuant to Paragraph 4 to Article 12. In
    this case, NRE and NRI shall take the measure of only reducing the purchase
    price to the extent of such damaged or lost portion thereof, with no
    obligation to repair whatsoever, and the Purchaser shall agree to this
    treatment without any objection. Further, neither NRE and NRI shall have any
    obligation. Regardless of the cause of claim such as warranty of no-latent
    defects, default, responsibility for unjust enrichment, for any damages
    whatsoever with respect to the Property.
4.  If the damage or loss of the Property does not amount to the degree set
    forth in Paragraph 1, NRE and NRI shall, after consultation with the
    Purchaser, take the measure of either (i) reducing the purchase price to the
    extent of such damaged or lost portion thereof, or (ii) doing repairs to the
    extent as set forth in Paragraph 1 of Article 6, and the Purchaser shall
    agree to the measure therefor being limited to either (i) or (ii) without
    any objection. In the case of either (i) or (ii) above, neither NRE or NRI
    shall have any obligation, regardless of the cause of the claim such as
    warranty of no-latent defects, default, responsibility in contract or tort,
    or responsibility for unjust enrichment, for any damages whatsoever with
    respect to the Property; provided, however, that if NRE and NRI choose
    option (ii), NRE and NRI shall be responsible for the warranty of no-latent
    defects relating to the defects which are caused from the portions of the
    Property subject to such repairs, to the extent as agreed upon by the
    Purchaser, NRE and NRI after consultations from time to time.

ARTICLE 20.
(Reservation of the Right of Purchaser to Termination during the Term.)
1.  Even after the execution of this Agreement, the Purchaser may terminate this
    Agreement during the period until the end of April, 2000 by notifying both
    NRE and NRI in writing that the Purchaser waives the money already paid to
    NRE and NRI pursuant to Paragraphs 1 and 2 of Article 4 hereof and
    terminates this Agreement.
2.  NRE and NRI may not terminate this Agreement even if they reimburse twice
    the amount of money received form the Purchaser pursuant to Paragraphs 1 and
    2 of Article 4 hereof.
<PAGE>
 
ARTICLE 21.
(Termination Due to Breach of this Agreement by Purchaser)
1.  In the event that the Purchaser fails to perform its material obligations
    hereunder against NRE and/or NRI, NRE and NRI may, by a written notice to
    the Purchaser under their joint names, terminate this Agreement after
    demanding a remedy in writing to the Purchaser under their joint names and
    such failure being remedied for seven (7) days (in the case of monetary
    obligations) or thirty (30) days (in the case of non-monetary obligations),
    as the case may be after receipt by the Purchaser of such demand.
2.  In the event of termination pursuant to the preceding paragraph, the
    Purchaser shall immediately pay to NRE and NRI, respectively, as a penalty
    for breach of contract, an amount equal to twenty percent (20%) of the
    purchase price as specified Articles 2 and 3 hereof. NRE and NRI shall apply
    the money received from the Purchaser pursuant to Paragraphs 1 and 2 of
    Article 4 hereof, to part of such penalty for breach of contract.
3.  The amount of the penalty for breach of contract under the preceding
    paragraph shall not change regardless of the actual amount of damages
    incurred by NRE and NRI.

ARTICLE 22.
(Termination Due to Breach of this Agreement by NRE only)
1.  In the event that only NRE fails to perform its material obligations
    hereunder, the Purchaser may, by written notice to NRE and NRI, terminate
    all of this Agreement or the portion of this Agreement relating to the sale
    and purchase between the Purchaser and NRE after demanding a remedy in
    writing to NRE and NRI and such failure being unremedied for seven (7) days
    (in the case of monetary obligations) or thirty (30) days (in the case of
    non-monetary obligations), as the case may be, after receipt by NRE of such
    demand. In this case, the Purchaser shall notify NRE and NRI in such
    termination notice of its decision to terminate either all of this Agreement
    or the portion of this Agreement relating to the sale and purchase between
    the Purchaser and NRE.
2.  If the portion of this Agreement relating to the sale and purchase between
    the Purchaser and NRE is terminated pursuant to the preceding paragraph, the
    Purchaser may demand form NRE the reimbursement of the money paid pursuant
    to Paragraph 1 of Article 4 hereof, and may demand any one of the following
    measures be taken. The Purchaser shall notify both NRE and NRI which of the
    following measures should be taken in the termination notice under the
    preceding paragraph.
    (1)  NRE shall immediately pay to the Purchaser as a penalty for breach of
         contract, an amount equal to twenty percent (20%) of the purchase price
         as specified in Article 2 hereof. The amount of the penalty for breach
         of contract shall not change regardless of the actual amount of damages
         incurred by the Purchaser.
    (2)  NRE and NRI shall consent to the Purchaser using part of the Property
         until March 31st, 2001 pursuant to the memorandum of Agreement
         Regarding Sublease, and NRE shall thereafter lease the Building to the
         Purchaser for ten (10) years from April 1st, 2001 to March 31, 2011
         pursuant in the Particulars of Building Lease Agreement attached
         hereto.
<PAGE>
 
3.  If the Purchaser elects to take the measures under Subparagraph (1) of the
    preceding paragraph, the portion of this Agreement relating to the sale and
    purchase between the Purchaser and NRI shall be automatically terminated. In
    such case, the Purchaser may not claim against NRE and/or NRI for any
    penalty for breach of contract, damages or other money arising out of or in
    connection with the termination, regardless of the name(s) or cause(s) of
    such claim, except for (i) the reimbursement of money from NRE under the
    text of the preceding paragraph (ii) the payment of the penalty-for-breach
    of contract from NRE under Subparagraph (1) of the preceding paragraph, and
    (iii) the reimbursement of money paid to NRI under Paragraph 2 of Article 4.
4.  If the Purchaser elects to take the measures under Subparagraph (2) of
    Paragraph 2, the Purchaser may not terminate the portion of this Agreement
    relating to the sale and purchase between the Purchaser and NRI, and may not
    claim against NRE and/or NRI for any penalty for breach of contract, damages
    or other money arising out of or in connection with the termination
    regardless of the name(s) or cause(s) of such claim, except for the claim
    for payment of the money against NRE under the text of Paragraph 2 above.
5.  If all of the Agreement is terminated pursuant to Paragraph 1 above, the
    Purchaser may demand from NRE and NRI the reimbursement of the money paid
    pursuant to Paragraphs 1 and 2 of Article 4 hereof, and may demand any one
    of the following measures be taken. The Purchaser shall notify both NRE and
    NRI which of the following measures should be taken in the termination
    notice under Paragraph 1 above.
    (1)  NRE shall immediately pay to the Purchaser as a penalty for breach of
         contract, and amount equal to twenty percent (20%) of the purchase
         price as specified in Article 2 hereof. The amount of the penalty for
         breach of contract shall not change regardless of the actual amount of
         damages incurred by the Purchaser. In this case, NRI shall not be
         responsible for the payment of such penalty for breach of contract to
         the Purchaser.
    (2)  NRE and NRI shall consent to the Purchaser using part of the Property
         until March 31st, 2001 pursuant to the Memorandum of Agreement
         Regarding Sublease, and thereafter, NRE shall lease the Building to the
         Purchaser, and NRI shall lease the Equipment/Fixtures II to the
         Purchaser, respectively, for ten (10) years from April 1st, 2001 to
         March 31st, 2011, pursuant to the Particulars of Building Lease
         Agreement attached hereto; provided, however, that the terms and
         conditions of the lease relating to the Equipment/Fixtures II shall be
         conferred and determined by the Purchaser, NRE and NRI, taking into
         account those set forth in the Office Space Sublease Agreement.
6.  If the Purchaser elects to take the measures under Subparagraph (1) of the
    preceding paragraph, the Purchaser may not claim against NRE and/or NRI for
    any penalty for breach of contract, damages or other money arising out of or
    in connection with the termination, regardless of the name(s) or cause(s) of
    such claim, except for (i) the reimbursement of money from both NRE and NRI
    under the text of the preceding paragraph, and (ii) the payment of the
    penalty for breach of contract from NRE under Subparagraph (1) of the
    preceding paragraph.
<PAGE>
 
7.  If the Purchaser elects to take the measures under Subparagraph (2) of
    Paragraph 5, the Purchaser may not claim against NRE and/or NRI for any
    penalty for breach of contract, damages or other money arising out of or in
    connection with the termination, regardless of the name(s) or cause(s) of
    such claim, except for the claim for payment of the money against both NRE
    and NRI under the text of Paragraph 5 above.

Article 23.
(Termination Due to Breach of this Agreement by NRI only)
1.  In the event that only NRI fails to perform its material obligations
    hereunder, the Purchaser may, by a written notice to NRE and NRI, terminate
    the portion of this Agreement relating to the sale and purchase between the
    Purchaser and NRI after making a demand for remedy in writing to NRE and NRI
    and such failure being unremedied for seven (7) days (in the case of
    monetary obligations) or thirty (30) days in the case of non-monetary
    obligations), as the case may be, after receipt by NRI of such demand.
2.  In the event of partial termination for this Agreement pursuant to the
    preceding paragraph, the Purchaser may demand from NRI the reimbursement of
    the money paid pursuant to paragraph 2 of Article 4 hereof, and may demand
    one of the following measures be taken, the Purchaser shall notify NRE and
    NRI which of the following measures should be taken in the termination
    notice under the preceding paragraph.
    (1)  NRI shall immediately pay to the Purchaser as a penalty for breach
         of contract, an amount equal to twenty percent (20%) of the purchase
         price as specified in Article 3 hereof. The amount of the penalty for
         breach of contract shall not change regardless of the actual amount of
         damages incurred by the Purchaser.
    (2)  NRE and NRI shall consent to the Purchaser using the Equipment/Fixtures
         II until March 31st, 2001 pursuant to the Memorandum of Agreement
         Regarding Sublease, and NRI shall lease the Equipment/Fixtures II to
         the Purchaser for ten (10) years from April 1st, 2001 to March 31st,
         2011; provided, however, that the terms and conditions of the lease
         shall be conferred and determined by the Purchaser, NRE and NRI, taking
         into account those set forth in the Office Space Sublease Agreement.
3.  If the Purchaser elects to take the measures under Subparagraph (1) of the
    preceding paragraph, the portion of this Agreement relating to the sale and
    purchase between the Purchaser and NRI shall be automatically terminated. In
    such case, the Purchaser may not claim against NRE and/or NRI for any
    penalty for breach of contract, damages or other money arising out of or in
    connection with the termination, regardless of the name(s) or cause(s) of
    such claim, except for (i) the reimbursement of money under text of
    Paragraph 1, (ii) the payment of the penalty for breach of contract under
    Subparagraph (1) of the preceding paragraph, and (iii) the reimbursement of
    money paid to NRE under Paragraph 1 of Article 4.
<PAGE>
 
4.  If the Purchaser elects to take the measures under Subparagraph (2) of
    Paragraph 2, the Purchaser may not terminate the portion of this Agreement
    relating to the sale and purchase between the Purchaser and NRI, and may not
    claim against NRE and/or NRI for any penalty for breach of contract, damages
    or other money arising out of or in connection with the termination,
    regardless of the name(s) or cause(s) of such claim, except for the claim
    for payment of the money against NRI under the text of Paragraph 2 above.

Article 24.
(Termination Due to Breach of this Agreement by NRE and NRI)
1.  In the event that NRE and NRI both fail to perform their respective material
    obligations hereunder, the Purchaser may, by a written notice to NRE and
    NRI, terminate this Agreement after making a demand for the remedy in
    writing to NRE and NRI and such failure being unremedied for seven (7) days
    (in the case of monetary obligations) or thirty (30) days (in the case of
    non-monetary obligations), as the case may be, after receipt by NRE and NRI
    of such demand.
2.  In the event of termination of this Agreement pursuant to the preceding
    paragraph, the Purchaser may demand from NRE and NRI, the reimbursement of
    money paid pursuant to Paragraphs 1 and 2 of Article 4 hereof, and may
    demand one of the following measures be taken. The Purchaser shall notify
    both NRE and NRI which of the following measures should be taken in the
    termination notice under the preceding paragraph.
    (1)  NRE and NRI shall immediately pay to the Purchaser as a penalty for
         breach of contract, an amount equal to twenty percent (20%) of the
         purchase price as specified in Articles 2 and 3 hereof. The amount of
         the penalty for breach of contract shall not change regardless of the
         actual amount of damages incurred by the Purchaser.
    (2)  NRE and NRI shall consent to the Purchaser using part of the Property
         until March 31st, 2001 pursuant to the Memorandum of Agreement
         Regarding Sublease, and for ten (10) years from April 1st, 2001 to
         March 31st, 2011 and NRE shall lease the Building to the Purchaser
         pursuant to the Particulars of Building Lease Agreement attached
         hereto, and NRI shall lease the Equipment/Fixtures II to the Purchaser;
         provided however, that the terms and conditions of the lease of the
         Equipment/Fixtures II shall be conferred and determined by the
         Purchaser NRE and NRI taking into account those set forth in the Office
         Space Sublease Agreement.
3.  If the Purchaser elects to take the measures under Subparagraph (1) of the
    preceding paragraph, this Agreement shall be automatically terminated. In
    such case, the Purchaser may not claim against NRE and/or NRI for any
    penalty for breach of contract, damages or other money arising out of or in
    connection with the termination, regardless of the name(s) or cause(s) of
    such claim, except for (i) the reimbursement of money under the text of
    Paragraph 1, and (ii) the payment of the penalty for breach of contract
    under Subparagraph (1) of the preceding paragraph.
<PAGE>
 
4.  If the Purchaser elects to take the measures under Subparagraph (2) of
    Paragraph 2, the Purchaser may not terminate this Agreement, and may not
    claim against NRE and/or NRI for any penalty for breach of contract, damages
    or other money arising out of or in connection with the termination,
    regardless of the name(s) or cause(s) of such claim, except for the claim
    for payment of the money against NRE and NRI under the text of Paragraph 2
    above.

Article 25.
(Limitation of Right to Termination)
The termination of this Agreement shall not become effective until and unless it
is made in the terms and manner set forth in the preceding six articles;
provided, however, that this shall not apply to the event where the text of
Paragraph 1 of Article 566 of the Civil Code, as referred to by Article 570 of
the Civil code, shall apply to the Land and the Building.

Article 26.
(Representations and Warranties)
1.  The Purchaser, NRE and NRI hereby represent and warrant to one another that
    all legal and internal procedures (including the resolutions for approval by
    the board of directors) necessary for the execution and performance of this
    Agreement are completed.
2.  NRE and NRI hereby represent and warrant to the Purchaser that, to the
    actual knowledge of NRE and NRI, there is no pending action suit,
    investigation, eminent domain action, or governmental notice with respect to
    the Property which materially affect the value of the Property.
3.  NRE and NRI hereby represent and warrant to the Purchaser that except as
    already disclosed to the Purchaser, to the extent that NRE and NRI can be
    aware of with reasonable diligence, there are no hazardous materials with
    respect to the Property, which would be generally recognized as materially
    harmful to any human life or body or as having materially adverse effect on
    the value of the Property.
4.  NRE and NRI hereby represent and warrant to the Purchaser that they have
    made the Purchaser review or have given an opportunity to review, all
    documents with respect to the Property on which NRE and NRI determine that
    the Purchaser have relied in making its representations in Article 16. For
    the avoidance of doubt, the documents which NRE and NRI have made the
    Purchaser review or have given an opportunity to review includes, but not
    limited to, those described in the Document Schedules I and II attached
    hereto.
5.  NRE and NRI hereby represent and warrant to the Purchaser that as of the
    execution date hereof, they have the insurance policies as set forth in the
    Insurance Schedule attached hereto and will keep them in place until the
    completion of the delivery of the Property and transfer of ownership of the
    Property to the Purchaser hereunder.
<PAGE>
 
6.  NRE and NRI hereby represent and warrant to the Purchaser that neither NRE
    nor NRI have any agreements or contracts to transfer the ownership or
    possession of the Property to any third party, or except for the already
    disclosed existing limitations or encumbrances, to establish on the
    Property, any security interest, including mortgage, maximal-hypothec,
    pledge and assignment-type mortgage, and any usufructuary rights including
    superficies and lease.
7.  NRE and NRI hereby represent and warrant to the Purchaser that for so long
    as this Agreement remains effective after the execution hereof, neither NRE
    nor NRI shall, without the prior written consent of the Purchaser, enter
    into any contracts or agreements regarding the Property that will survive
    the transfer of ownership to the Purchaser, and that to the extent there are
    such outstanding contracts or agreements, NRE and/or NRI will discharge of
    extinguish all of its obligations and liabilities under such contracts and
    agreements before the transfer of ownership of the Property to the
    Purchaser.

Article 27.
(Covenants)
1.  During the period from the execution hereof to the delivery of the Property,
    NRE and NRI shall manage the Property, with due diligence of good manager at
    the same level as NRE and NRI continued to manage it so far, to the extent
    as provided for herein in accordance with their respective ownership
    portions of the Property, and use the Property in accordance with the
    provisions of the Memorandum of Agreement regarding Lease and the Office
    Space Sublease Agreement.
2.  For so long as this Agreement remains effective after the execution hereof,
    neither NRE nor NRI shall transfer the ownership or possession of the
    Property to any third party, or, except for the existing limitations or
    encumbrances, establish on the Property, any security interest including
    mortgage, maximal-hypothec, pledge and assignment-type mortgage, and any
    usufructuary rights including superficies and lease.
3.  For so long as this Agreement remains effective after the execution hereof,
    neither NRE nor NRI shall provide any information of the Property of the
    real estate market.
4.  For so long as this Agreement remains effective after the execution hereof,
    if any of the Purchaser, NRE and NRI are aware of the occurrence of any
    event which would have material effect on the Property, such party shall
    notify the other parties thereof and shall in good faith confer with the
    other parties on the measures therefor.

Article 28.
(Management Service Agreement of the Property)
1.  The Purchaser shall, after the execution of this Agreement and before the
    delivery of the Property, discuss in good faith with Nomura Building Sogo
    Kanri K.K. ("Nomura Building Management") with respect to an agreement
    regarding the entrustment of the management of the Property. Provided,
    however, that if the Purchaser and Nomura Building Management fail to reach
    an agreement, the Purchaser may enter into an agreement regarding the
    entrustment of the management of the Property with a third party.
<PAGE>
 
2.  The contents of the management service agreement by and between the
    Purchaser and Nomura Building Management shall be specified separately by
    and between the Purchaser and Nomura Building Management.
3.  If the management service agreement is entered into by and between the
    Purchaser and Nomura Building Management before the delivery of the
    Property, the delivery of the portion possessed by Nomura Building
    Management under Paragraph 1 of Article 9 shall be made by the method of
    "transfer of possession by direction (sasizu-ni-yoru-senyuiten) provided for
    in Article 184 of the Civil Code.
4.  NRE and NRI shall bear no responsibility to the Purchaser with respect to
    the management service performed by Nomura Building Management.

Article 29.
(Measures for Jamming Prevention)
1.  The Purchaser acknowledges without any objection that in order to remove TV
    radio disturbance or other jamming caused by the effect of the Building, NRE
    has agreements with its neighbors pursuant to which (i) NRE shall allow
    neighbors to gratuitously use the TV audience common facilities set up in
    the Building for neighbors (ii) NRE shall bear the expenses for the
    maintenance, repair, administration and renewal of the TV audience common
    facilities for neighbors, and (iii) NRE shall pay to Tokyo Electric Power
    Co., Inc,. the charges for installment and electricity relating to the TV
    audience common facilities for neighbors.
2.  In the event that the Purchaser acquires the ownership of the Building, the
    Purchaser shall succeed from NRE all its obligations under the agreements
    with the neighbors in the preceding paragraph with NRE being released from
    all its obligations, and shall comply with all such agreements.
3.  NRE represents and warrants that it has provided the Purchaser with a true
    and correct copy of all documents (which shall be limited to originals)
    related to the TV audience common facilities set forth in Paragraph 1, to
    the extent that NRE actually recognizes and holds such documents, as at the
    time of the execution hereof.
4.  If the Purchaser establishes equipment or other structures (including
    antennas) on the Building and cause any TV and/or radio disturbance or other
    jamming to neighbors due to the effect of such equipment or structures, the
    Purchaser shall, in its sole responsibility and expense, take appropriate
    measure therefore and shall not cause any trouble to NRE or NRI.

Article 30
(Assignment of Rights and Obligations)
The Purchaser may not assign or transfer its contractual status as seller
hereunder or any of its rights or obligations hereunder to any third party,
without the written consent of NRE and NRI, which consent shall not unreasonably
withheld or delayed.

Article 31.
(Individual Obligations)
Any monetary obligations which NRE and NRI shall have under this Agreement shall
not be joint and several, regardless of the cause(s) thereof.
<PAGE>
 
Article 32.
(Notification)
Any notification which the Purchaser, NRE or NRI makes under this Agreement
shall not be effective unless made in writing.

Article 33.
(Confidentiality)
Neither the Purchaser, NRE, nor NRI shall use any confidential information
obtained in the discussions and negotiations relating to this Agreement, the
Memorandum of Agreement Regarding Sublease and the Office Space Sublease
Agreement for any purpose other than the execution of this Agreement, the
Memorandum of Agreement Regarding Sublease or the Office Space Sublease
Agreement, and shall not disclose such confidential information to any third
party except as required by law or with the consent of the other parties. The
parties may disclose such confidential information to their legal and financial
advisors provided their advisors, if not subject to statutory confidential
obligations, enter into a confidentiality agreement in advance.

Article 34.
(Default Interest)
The default interest in the event of default in respect of monetary obligations
hereunder shall be calculated at the per-diem rate of 14.6 percent on a 365-day
year basis.

Article 35.
(Cost Allocation of Stamp Duty)
The stamp duty to be affixed to this Agreement shall be borne by the Purchaser
and NRE, respectively.

Article 36.
(Governing Law and Jurisdiction)
This Agreement shall be governed and construed in accordance with the laws of
Japan, and any dispute relating to this Agreement shall be submitted to the
exclusive jurisdiction of the Tokyo District Court in the first instance.

Article 37.
(Language)
This Agreement was prepared in Japanese with an English translation thereof.
Should there be any difference or inconsistency between the Japanese version and
the English version, the Japanese version shall prevail in all respects.
<PAGE>
 
Article 38.
(Binding Effect of Agreement before Execution of this Agreement)
1.  The execution of this Agreement shall in no way affect the effect of the
    Memorandum of Agreement regarding Sublease and the Office Space Sublease
    Agreement
2.  Except for the Memorandum of Agreement Regarding Sublease and the Office
    space Sublease Agreement, any matters agreed to by and between the Purchaser
    and NRE and NRI prior to the execution of this Agreement, whether in
    writing, oral or otherwise and irrespective of the form it takes and its
    name, shall be null and void.
3.  If any portion of the provisions of this Agreement is found to be void or
    unenforceable by a decision etc. by a court, such provision shall not be
    effective; provided, however, that the avoidance or unenforceability of such
    provision shall not affect the validity and enforceability of the other
    provisions hereof. The Purchaser, NRE and NRI agree to amend or alter such
    provision to the extent that it is necessary to be valid and enforceable,
    considering the purpose and effect of such provision.

Article 39.
(Conditions Precedent to the Purchaser's Obligation to Purchase)
1.  The following are conditions precedent to the Purchaser's obligations to pay
    the remaining balance under each paragraph of Article 2 and Paragraph 1 of
    Article 4. The failure by NRE to perform any of the following conditions
    shall be deemed as a breach of the "material obligations" referred to in
    Articles 22, 23 and 24 hereof, and Articles 22, 23 and 24 shall apply to
    such cases:
    (1)  NRE shall deliver to the Purchaser a writing that the representations
         and warranties of NRE set forth in each paragraph of Article 26 are
         true and correct as of the date of delivery of the Land and the
         Building with the same force and effect as if they had been made at
         such date;
    (2)  NRE shall deliver a certified copy of the real estate registry
         regarding the Land and Building, representing no security interest
         including any mortgage, maximal-hypothec, pledge and assignment-type
         mortgage and no usufructuary rights including superficies and lease
         thereon; and
    (3)  Upon delivery of the Land and the Building, NRE shall deliver to the
         Purchaser a writing that NRE is not aware of the occurrence of, since
         the date hereof, any event which makes any material adverse effect on
         the Land and the Building and which has not been disclosed pursuant to
         Paragraph 4 of Article 27 hereof.
<PAGE>
 
2.  The following are conditions precedent to the Purchaser's obligations to pay
    the remaining balance under each paragraph of Article 3 and Paragraph 2 of
    Article 4. The failure by NRI to perform any of the following conditions
    shall be deemed as a breach of the "material obligations" referred to in
    Articles 22 through 24 hereof, and Articles 22 through 24 shall apply to
    such cases:
    (1)  NRI shall deliver to the Purchaser a writing that the representations
         and warranties of NRI set forth in each paragraph of Article 26 are
         true and correct as of the date of delivery of the Equipment/Fixtures
         II with the same force and effect as if they had been made at such
         date; and
    (2)  Upon delivery of the Equipment/Fixtures II, NRI shall deliver to the
         Purchaser a writing that NRI is not aware of, since the date hereof,
         the occurrence of any event which makes any material adverse effect on
         the Equipment/Fixtures II and which has not been disclosed to the
         Purchaser pursuant to the Paragraph 4 of Article 27 hereof.

Article 40.
(Matters not Provided For)
With respect to any matter which is not provided for in this Agreement, the
Purchaser, NRE, and NRI shall in good faith confer and resolve such matters in
accordance with the Civil Code, other relevant laws and regulations, and the
practices of real estate lease transactions in Japan.
<PAGE>
 
IN WITNESS WHEREOF, the parties have caused this Agreement executed in duplicate
to be signed and sealed, the Purchaser and NRE each shall retain one original,
and NRI shall retain one copy.

April 25, 2000

                           Purchaser: EXODUS COMMUNICATIONS, K.K.
                                      /s/  ILLEGIBLE

                           NRE:       NOMURA REAL ESTATE DEVELOPMENT, CO. LTD.
                                      /s/  ILLEGIBLE

                           NRI:       NOMURA RESEARCH INSTITUTE, LTD.
                                      /s/  ILLEGIBLE