
<PAGE>

                       F5 LABS, INC. AMENDED AND RESTATED

                    DIRECTORS' NONQUALIFIED STOCK OPTION PLAN

                    (Revised effective as of October 1, 1998)

         This Amended and Restated Nonqualified Stock Option Plan (the "Plan")
provides for the grant of options to acquire shares of Common Stock, no par
value (the "Common Stock"), of F5 Labs, Inc., a Washington corporation (the
"Company"). Stock options granted under this Plan (the "Options" or "Option")
are intended to be nonstatutory stock options which do not qualify under Section
422 of the Internal Revenue Code of 1986, as amended (the "Code").

         1. PURPOSE. The purpose of this Plan is to compensate certain directors
of the Company (the "Optionees" or "Optionee").

         2. ADMINISTRATION. This Plan shall be administered by the Board of
Directors of the Company (the "Board"), except that the Board may, in its
discretion, establish a committee composed of members of the Board or other
persons to administer this Plan, which committee (the "Committee") may be an
executive, compensation or other committee, including a separate committee
especially created for this purpose. The Committee shall have such of the powers
and authority vested in the Board hereunder as the Board may delegate to it
(including the power and authority to interpret any provision of this Plan or of
any Option). The members of any such Committee shall serve at the discretion of
the Board. The Board, or the Committee if one has been established by the Board,
are referred to in this Plan as the "Plan Administrator." Following registration
of any of the Company's securities under Section 12 of the Securities Exchange
Act of 1934, as amended (the "Exchange Act"), no person shall serve as a member
of the Plan Administrator if his or her service would disqualify this Plan from
eligibility under Securities and Exchange Commission Rule 16b-3, as amended from
time to time, or any successor rule or regulatory requirements; PROVIDED, that
the Plan Administrator shall consist of at least the minimum number of persons
required by Securities and Exchange Commission Rule 16b-3, as amended, or any
successor rule or regulatory requirements.

         Subject to the provisions of this Plan, and with a view to effecting
its purpose, the Plan Administrator shall have sole authority, in its absolute
discretion, to: (a) construe and interpret this Plan; (b) define the terms used
in this Plan; (c) prescribe, amend and rescind rules and regulations relating to
this Plan; (d) correct any defect, supply any omission or reconcile any
inconsistency in this Plan; (e) determine the exercise price of each Option, the
duration of each Option and the times at which each Option shall become
exercisable; (f) determine all other terms and conditions of Options; and (g)
make all other determinations necessary or advisable for the administration of
this Plan. All decisions, determinations and interpretations made by the Plan
Administrator shall be binding and conclusive on all participants in this Plan
and on their legal representatives, heirs and beneficiaries.

         3. ELIGIBILITY. Persons eligible to receive options under this Plan
shall be all directors of the Company who are not otherwise employed by the
Company or any Related Corporation, as defined below (the "Directors" or
"Director"). Options may be granted in substitution for outstanding Options of
another corporation in connection with the merger,



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<PAGE>




consolidation, acquisition of property or stock or other reorganization between
such other corporation and the Company or any subsidiary of the Company. Options
also may be granted in exchange for outstanding Options.

         As used in this Plan, the term "Related Corporation," when referring to
a subsidiary corporation, shall mean any corporation (other than the Company) in
an unbroken chain of corporations beginning with the Company if, at the time of
the granting of the Option, each of the corporations other than the last
corporation in the unbroken chain owns stock possessing fifty percent (50%) or
more of the total combined voting power of all classes of stock of one of the
other corporations in such chain. When referring to a parent corporation, the
term "Related Corporation" shall mean any corporation (other than the Company)
in an unbroken chain of corporations ending with the Company if, at the time of
granting of the Option, each of the corporations other than the Company owns
stock possessing fifty percent (50%) or more of the total combined voting power
of all classes of stock of one of the other corporations in such chain.

         4. STOCK. Subject to approval of the Plan by shareholders of the
Company, each individual who, subsequent to the closing of the Company's Series
A Preferred Stock financing and prior to the Company's Series D Preferred Stock
financing, becomes a Director of the Company, and who is not otherwise an
employee of the Company or any Related Corporation or is not elected as a
Director in direct connection with his or her investment in the Company (or with
an investment in the Company by an entity with whom he or she is affiliated or
by which he or she is designated as a representative), shall automatically be
issued options to acquire 42,000 shares of Common Stock of the Company. No
options shall be granted under the Plan after the closing of the Company's
Series D Preferred Stock financing. Options to purchase up to the maximum number
of shares of Common Stock which may be granted pursuant to the Company's Amended
and Restated 1996 Stock Option Plan, as such plan may be amended from time to
time hereafter (subject to adjustment as provided in the Company's Amended and
Restated 1996 Stock Option Plan) in the aggregate may be issued pursuant to the
Plan, LESS any shares issuable upon the exercise of Options granted under the
Company's Amended and Restated 1996 Stock Option Plan. The number of options
available for a grant hereunder is further subject to adjustment as set forth in
Section 5.12 hereof. In the event that any outstanding Option expires or is
terminated for any reason, those shares of Common Stock allocable to the
unexercised portion of such Option may be subject to one or more other Options
issued pursuant to the Plan or the Company's Amended and Restated 1996 Stock
Option Plan.

         5. TERMS AND CONDITIONS OF OPTIONS. Each Option shall be evidenced by a
written agreement (the "Agreement") in the form approved by the Company.
Agreements may contain such additional provisions, not inconsistent herewith, as
the Company in its discretion may deem advisable. All Options shall also comply
with the following requirements:

         5.1 NUMBER OF SHARES. Each Agreement shall state the number of shares
to which it pertains.

         5.2 DATE OF GRANT. Each Option shall state the date the Company and the
Director entered into the Agreement (the "Date of Grant"), which shall be a date
that is no more 


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<PAGE>


than thirty (30) days following the approval of this Plan by the shareholders of
the Company, or, in the case of new Directors, the date the individual becomes a
Director, whichever is applicable.

         5.3 OPTION PRICE. The exercise price for all Options granted hereunder
shall be the fair market value on Date of Grant, as determined by the Plan
Administrator.

         5.4 VESTING SCHEDULE. All Options shall vest according to the following
schedule:


<TABLE>
<CAPTION>

                                                            Percentage of
              Number of Years                               Total Option to
         Following Date of Grant                            Be Exercisable
         -----------------------                            -----------------

<S>                                                              <C>
                  1                                                33 1/3%
                  2                                                66 2/3%
                  3                                                100%
</TABLE>

         5.5 ACCELERATION OF VESTING. Options granted pursuant to the Plan shall
become immediately vested and fully exercisable upon the Director's termination
as a director of the Company by reason of the death or Disability (as defined in
Section 5.6 below) of the Director. The vesting of Options shall also be
accelerated under the circumstances described in Sections 5.12 and 5.13 below.

         5.6 TERMINATION OF OPTION. A vested Option shall terminate, to the
extent not previously exercised, upon the occurrence of the first of the
following events:

             (i) ten (10) years from the Date of Grant;

             (ii) the expiration of ninety (90) days from the date of 
Optionee's termination as a Director of the Company for any reason other than 
death or Disability (as defined below); or

             (iii) the expiration of one (1) year from the date of death of 
Optionee or the cessation of Optionee's service as a Director by reason of 
Disability (as defined below).

         "Disability" shall mean that a person is unable to engage in any
substantial gainful activity by reason of any medically determinable physical or
mental impairment that can be expected to result in death or that has lasted or
can be expected to last for a continuous period of not less than twelve (12)
months. If Optionee's service as a Director is terminated by death, any Option
held by Optionee shall be exercisable only by the person or persons to whom such
Optionee's rights under such Option shall pass by Optionee's will or by the laws
of descent and distribution of the state or country of Optionee's domicile at
the time of death. Each unvested Option granted pursuant hereto shall terminate
upon Optionee's termination as a Director for any reason whatsoever, including
death or Disability.


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<PAGE>


         5.7 EXERCISE OF OPTIONS. Options shall be exercisable, either all or in
part, at any time after vesting. If less than all of the shares included in the
vested portion of any Option are purchased, the remainder may he purchased at
any subsequent time prior to the expiration of the Option term. No portion of
any Option of less than one (1) share (as adjusted pursuant to Section 5.12
below) may be exercised; PROVIDED, that if the vested portion of any Option is
less than fifty (50) shares, it may be exercised with respect to all shares for
which it is vested. Only whole shares may be issued pursuant to an Option, and
to the extent that an Option covers less than one share, it is unexercisable.
Options or portions thereof may be exercised by giving to the Company an
executed notice of election to exercise, which notice shall specify the number
of shares to be purchased, and be accompanied by payment in the amount of the
aggregate option price for the Common Stock so purchased and in the form
specified in Section 5.8 below. The Company shall not be obligated to issue,
transfer or deliver a certificate of Common Stock to any Director, or to his
personal representative, until the aggregate option price has been paid for all
shares for which the Option shall have been exercised and adequate provision has
been made by the Optionee for the satisfaction of any tax withholding
obligations associated with such exercise. During the lifetime of an Optionee,
Options are exercisable only by Optionee.

         5.8 PAYMENT UPON EXERCISE OF OPTION. Upon exercise of any option, the
aggregate option price shall be paid to the Company in cash or by certified or
cashier's check. Alternatively, a Director may pay for all or any portion of the
aggregate option exercise price (i) by delivering to the Company shares of
Common Stock previously held by such Director, (ii) having shares withheld from
the amount of shares of Common Stock to be received by the Director or (iii)
delivering an irrevocable subscription agreement obligating the Director to take
and pay for the shares of common Stock to be purchased within one (1) year of
the date of exercise. The shares of Common Stock received or withheld by the
Company as payment for shares of Common Stock purchased upon the exercise of
Options shall have a fair market value at the date of exercise (as determined in
accordance with Section 5.3 above) equal to the aggregate option exercise price
(or portion thereof) to be paid by the Director upon exercise.

         5.9 RIGHTS AS A SHAREHOLDER. An Optionee shall have no rights as a
shareholder with respect to any shares covered by the Option until such Optionee
becomes a record holder of such shares, irrespective of whether such Optionee
has given notice of exercise. Subject to the provisions of Sections 5.12 and
5.13 below, no rights shall accrue to an Optionee and no adjustments shall be
made on account of dividends (ordinary or extraordinary, whether in cash,
securities or other property) or distributions or other rights declared on, or
created in, the Common Stock for which the record date is prior to the date the
Optionee becomes a record holder of the shares of Common Stock covered by the
Option, irrespective of whether such Optionee has given notice of exercise.

         5.10 TRANSFER OF OPTION. Options granted under this Plan and the rights
and privileges conferred by this Plan may not be transferred, assigned, pledged
or hypothecated in any manner (whether by operation of law or otherwise) other
than by will or by applicable laws of descent and distribution, as defined by
the Code, or the Employee Retirement Income Security Act, or the rules and
regulations thereunder, and shall not be subject to execution, attachment or
similar process. Upon any attempt to transfer, assign, pledge, hypothecate or
otherwise dispose of any Option or of any right or privilege conferred by this
Plan contrary to the provisions hereof, 


                                       4
<PAGE>


or upon the sale, levy or any attachment or similar process upon the rights and
privileges conferred by this Plan, such Option shall thereupon terminate and
become null and void.

         5.11 SECURITIES REGULATION AND TAX WITHHOLDING

              5.11.1 Shares shall not be issued with respect to an Option 
unless the exercise of such Option and the issuance and delivery of such 
shares shall comply with all relevant provisions of law, including, without 
limitation, any applicable state securities laws, the Securities Act of 1933, 
as amended, the Securities Exchange Act of 1934, as amended, the rules and 
regulations thereunder and the requirements of any stock exchange upon which 
such shares may then be listed, and such issuance shall be further subject to 
the approval of counsel for the Company with respect to such compliance, 
including the availability of an exemption from registration for the issuance 
and sale of such shares. The inability of the Company to obtain from any 
regulatory body the authority deemed by the Company to be necessary for the 
lawful issuance and sale of any shares under this Plan, or the unavailability 
of an exemption from registration for the issuance and sale of any shares 
under this Plan, shall relieve the Company of any liability with respect to 
the non-issuance or sale of such shares.

         As a condition to the exercise of an Option, the Company may require
the Optionee to represent and warrant in writing at the time of such exercise
that the shares are being purchased only for investment and without any
then-present intention to sell or distribute such shares. At the option of the
Company, a stop-transfer order against such shares may be placed on the stock
books and records of the Company, and a legend indicating that the stock may not
be pledged, sold or otherwise transferred unless an opinion of counsel is
provided stating that such transfer is not in violation of any applicable law or
regulation, may be stamped on the certificates representing such shares in order
to assure an exemption from registration. The Company also may require such
other documentation as may from time to time be necessary to comply with federal
and state securities laws. THE COMPANY HAS NO OBLIGATION TO UNDERTAKE
REGISTRATION OF OPTIONS OR THE SHARES OF STOCK ISSUABLE UPON THE EXERCISE OF
OPTIONS.

              5.11.2 As a condition to the exercise of any Option granted 
under this Plan, the Optionee shall make such arrangements as the Company may 
require for the satisfaction of any federal, state or local withholding tax 
obligations that may arise in connection with such exercise.

              5.11.3 The issuance, transfer or delivery of certificates of 
Common Stock pursuant to the exercise of Options may be delayed, at the 
discretion of the Board, until the Company is satisfied that the applicable 
requirements of the federal and state securities laws and the withholding 
provisions of the Code have been met.

                                       5
<PAGE>


         5.12 STOCK DIVIDEND, REORGANIZATION OR LIQUIDATION

              5.12.1 If (i) the Company shall at any time be involved in a 
transaction described in Section 424(a) of the Code (or any successor 
provision) or any "corporate transaction" described in the regulations 
thereunder; (ii) the Company shall declare a dividend payable in, or shall 
subdivide or combine, its Common Stock or (iii) any other event with 
substantially the same effect shall occur, the number of shares of Common 
Stock and/or the exercise price per share of each outstanding Option shall be 
proportionately adjusted so as to preserve the rights of the Optionee 
substantially proportionate to the rights of the Optionee prior to such 
event, and to the extent that such action shall include an increase or 
decrease in the number of shares of Common Stock subject to outstanding 
Options, the number of shares available under Section 4 of this Plan shall 
automatically be increased or decreased, as the case may be, proportionately, 
without further action on the part of the Company or the Company's 
shareholders. For example, in the event the Company declares a 2-for-1 stock 
dividend (i) the number of shares of Common Stock authorized for issuance 
under this Plan pursuant to section 4 above shall automatically be increased 
by 600,000 shares of Common Stock to an aggregate of 900,000 shares of Common 
Stock and (ii) the number of shares issuable upon exercise of each Option 
then outstanding shall automatically be tripled and the exercise price per 
share shall automatically be reduced by two-thirds.

              5.12.2 If the Company is liquidated or dissolved, the holders 
of any outstanding Options may exercise all or any part of the unvested 
portion of the Options held by them; PROVIDED, that such Options must be 
exercised prior to the effective date of such liquidation or dissolution. If 
the Option holders do not exercise their Options prior to such effective 
date, each outstanding Option shall terminate as of the effective date of the 
liquidation or dissolution.

              5.12.3 The grant of an Option shall not affect in any way the 
right or power of the Company to make adjustments, reclassifications, 
reorganizations or changes of its capital or business structure, to merge, 
consolidate or dissolve, to liquidate or to sell or transfer all or any part 
of its business or assets.

         5.13 CHANGE IN CONTROL; DECLARATION OF EXTRAORDINARY DIVIDEND

              5.13.1 CHANGE IN CONTROL. If at any time there is a Change in 
Control (as defined below) of the Company, all Options shall accelerate and 
become fully vested and immediately exercisable for the duration of the 
Option term. For purposes of this Subsection 5.13.1, "Change in Control" 
shall mean either one of the following: (i) When any "person," as such term 
is used in sections 13(d) and 14(d) of the Exchange Act (other than a 
shareholder of the Company on the date of this Plan, the Company, a 
Subsidiary or an employee benefit plan of the Company, including any trustee 
of such plan acting as trustee) becomes, after the date of this Plan, the 
"beneficial owner" (as defined in Rule 13d-3 under the Exchange Act), 
directly or indirectly, of securities of the Company representing fifty 
percent (50%) or more of the combined voting power of the Company's then 
outstanding securities; or (ii) the occurrence of a transaction requiring 
shareholder approval, and involving the sale of all or substantially all of 
the assets of the Company or the merger of the Company with or into another 
corporation.

                                       6
<PAGE>


              5.13.2 DECLARATION OF EXTRAORDINARY DIVIDEND. If at any time 
the Company declares an Extraordinary Dividend (as defined below), all 
Options shall accelerate and thereupon become fully vested and immediately 
exercisable for the duration of the Option term. For purposes of this 
Subsection 4.13.2, "Extraordinary Dividend" shall mean a cash dividend 
payable to holders of record of the Common Stock in an amount in excess of 
ten percent (10%) of the then fair market value of the Company's Common 
Stock. The fair market value of the Company's Common Stock shall be 
determined in good faith by the Board.

         6. EFFECTIVE DATE; TERM. Subject to approval of this Plan by
shareholders of the Company, this Plan shall be effective as of the date which
is the first Date of Grant specified in Section 5.2 above, and Options may be
issued then and from time to time thereafter until this Plan is terminated by
the Company. Termination of this Plan shall not terminate any Option granted
prior to such termination.

         7. NO OBLIGATIONS TO EXERCISE OPTION. The granting of an Option shall
impose no obligation upon the Optionee to exercise such Option.

         8. APPLICATION OF FUNDS. The proceeds received by the Company from the
sale of Common Stock, pursuant to the exercise of Options granted hereunder,
will be used for general corporate purposes.

         9. INDEMNIFICATION OF BOARD. In addition to all other rights or
indemnification they may have as directors of the Company or as members of the
Board, members of the Board shall be indemnified by the Company for all
reasonable expenses and liabilities of any type and nature, including reasonable
attorneys fees, incurred in connection with any action, suit or proceeding to
which they or any of them are a party by reason of, or in connection with, the
Plan or any Option granted hereunder, and against all amounts paid by them in
settlement thereof (provided such settlement is approved by independent legal
counsel selected by the Company), except to the extent that such expenses relate
to matters for which it is adjudged that such Board members are liable for
willful misconduct; PROVIDED, that within fifteen (15) days after the
institution of any such action, suit or proceeding, member(s) of the Board
shall, in writing, notify the Company of such action, suit or proceeding, so
that the Company may have the opportunity to make appropriate arrangements to
prosecute or defend the same.

         10. AMENDMENT OF PLAN. The Plan Administrator may, at any time, modify,
amend or terminate this Plan and Options granted under this Plan, including,
without limitation, such modifications or amendments as are necessary to
maintain compliance with applicable statutes, rules or regulations; PROVIDED,
that no amendment with respect to an outstanding Option shall be made over the
objection of the Optionee thereof and PROVIDED FURTHER, that after registration
of any of the Company's securities under Section 12 of the Securities Exchange
Act of 1934, as amended: (i) the approval of the holders of a majority of the
Company's outstanding shares of voting capital stock represented at a meeting at
which a quorum is present is required within twelve (12) months before or after
the adoption by the Board of any amendment that will permit the granting of
Options to a class of persons other than those currently eligible to receive
Options under this Plan or that would cause this Plan to no longer comply with
Securities and Exchange 


                                       7
<PAGE>


Commission Rule 16b-3, as amended, or any successor rule or other regulatory
requirements and (ii) this Plan shall not be amended more than once every six
(6) months, other than to comport with changes in the Code, the Employee
Retirement Security Act, or the rules thereunder.




                                       8

