Exhibit 99.3

UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS

The following unaudited pro forma condensed combined balance sheet as of September 30, 2013 and the unaudited pro forma condensed combined statements of income (loss) for the three months ended September 30, 2013 and for the fiscal year ended June 30, 2013 are based on the historical financial statements of Extreme Networks, Inc.(“Extreme” or the “Company”), and Enterasys Networks, Inc. (“Enterasys”) after giving effect to Extreme’s acquisition of Enterasys using the acquisition method of accounting and borrowing pursuant to the term loan and revolving credit facility to finance the Enterasys acquisition, and after applying the assumptions, reclassifications and adjustments described in the accompanying notes to the unaudited pro forma condensed combined financial statements.

Extreme and Enterasys have different fiscal year ends. Accordingly, the unaudited pro forma condensed combined balance sheet as of September 30, 2013 combines Extreme’s historical unaudited condensed consolidated balance sheet as of September 30, 2013 and Enterasys’ historical audited consolidated balance sheet as of September 30, 2013 and is presented as if the acquisition of Enterasys had occurred on September 30, 2013 and includes all adjustments that give effect to events that are directly attributable to the acquisition of Enterasys and that are factually supportable. The unaudited pro forma condensed combined statement of income (loss) for the three months ended September 30, 2013 combines the unaudited historical results of Extreme for the three months ended September 30, 2013 and the unaudited historical results of Enterasys for the three months ended September 30, 2013. The unaudited pro forma condensed combined statement of income (loss) for the fiscal year ended June 30, 2013 combines the audited historical results of Extreme for the year ended June 30, 2013 and the audited historical results of Enterasys for the year ended September 30, 2013. The unaudited pro forma condensed combined statements of income (loss) are presented as if the acquisition had occurred on July 1, 2012 and include adjustments that give effect to events that are directly attributable to the acquisition of Enterasys, expected to have a continuing impact and that are factually supportable.

The unaudited pro forma condensed combined financial statements are based on the estimates and assumptions set forth in the notes to such statements, which are preliminary and have been made solely for purposes of developing such pro forma information. The unaudited pro forma condensed combined financial statements are not intended to represent or be indicative of the results that would have been achieved had the acquisition been consummated and the borrowings pursuant to the term loan and revolving credit facility been completed as of the date indicated or that may be achieved in the future.

The acquisition has been accounted for using the acquisition method of accounting.  The estimated purchase price has been allocated on a preliminary basis to tangible and intangible assets acquired and liabilities assumed.  The final purchase price allocation is pending the finalization of appraisal valuations, which may result in an adjustment to the preliminary purchase price allocation. Also, additional information which existed as of the acquisition date but was unknown to the Company at that time, may become known to the Company during the remainder of the measurement period, a period not to exceed 12 months from the acquisition date, may result in a change in the purchase price allocation.  While management believes that its preliminary estimates and assumptions underlying the valuations are reasonable, different estimates and assumptions could result in different valuations assigned to the individual assets acquired and liabilities assumed, and the resulting amount of goodwill.

The unaudited pro forma condensed combined financial statements do not include the realization of future cost savings or synergies or the effects of any future restructuring activities that pertain to Extreme’s operations.  These future restructuring expenses may be material and may include costs for severance, costs for vacating facilities and costs to exit or terminate other duplicative activities.  Future restructuring expenses will be recorded in the period that these expenses become probable and can be estimated or are incurred.

These unaudited pro forma condensed combined financial statements should be read in conjunction with Extreme’s historical consolidated financial statements and notes thereto contained in Extreme’s Annual Report on Form 10-K for its fiscal year ended June 30, 2013 and Quarterly Report on Form 10-Q for its three months ended September 30, 2013 and Enterasys’ historical consolidated financial statements and notes thereto contained herein for its fiscal year ended September 30, 2013 and 2012, which is included as Exhibit 99.1 and for its fiscal year ended September 30, 2012 and 2011, which is included as Exhibit 99.2 to this Form 8-K/A.

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EXTREME NETWORKS, INC.

UNAUDITED PRO FORMA CONDENSED CONSOLIDATED BALANCE SHEETS

As of September 30, 2013

(In thousands, except per share amounts)

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EXTREME NETWORKS, INC.

UNAUDITED PRO FORMA CONDENSED COMBINED STATEMENT OF OPERATIONS

For the Three Months Ended September 30, 2013

(In thousands, except per share amounts)

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EXTREME NETWORKS, INC.

UNAUDITED PRO FORMA CONDENSED COMBINED STATEMENT OF OPERATIONS

For the Year Ended June 30, 2013

(In thousands, except per share amounts)

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NOTES TO UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS

1. Description of the Transaction

On October 31, 2013 (the “Acquisition Date”), Extreme Networks, Inc. (“Extreme ” or “the Company”) completed the acquisition of Enterasys Networks, Inc. (“Enterasys”), a privately held provider of wired and wireless network infrastructure and security solutions, for $180 million in cash.  Also, on October 31, 2013, the Company entered into a $125 million senior secured credit facilities agreement consisting of a $65 million term loan facility (“Term Loan”) and a revolving credit facility of $60 million (“Revolving Facility”).  Both facilities mature on October 31, 2018.  The proceeds from the Term Loan were used to pay a portion of the purchase price in the acquisition of all of the issued and outstanding capital stock of Enterasys. The company also drew $35 million of the $60 million Revolving Facility to pay a portion of the purchase price in the acquisition of all of the issued and outstanding capital stock of Enterasys.

2. Preliminary Purchase Price

On October 31, 2013, Extreme completed its acquisition of Enterasys such that Enterasys became a wholly owned subsidiary of Extreme. Cash of $180 million was paid at the Acquisition Date with remaining amounts, if any, to be based on working capital adjustments as defined in the agreement.  These adjustments have not been finalized as of the date of this filing.

3. Preliminary Purchase Price Allocation

The estimated purchase price has been allocated to Enterasys’ estimated tangible and identifiable intangible assets acquired and liabilities assumed on a preliminary basis as follows (in thousands):

For the purposes of the pro forma financial statements, the estimated purchase price stated above has been allocated based on the preliminary estimates of the fair value of the assets acquired and liabilities assumed as of the balance sheet date presented.  The final purchase price allocation will be based on the estimated fair values at the acquisition date and could vary significantly from the pro forma amounts.

The $108.9 million of acquired identifiable intangibles have a weighted-average useful life of approximately three years.  The definite-lived intangible assets include developed technology of $45 million (3-year weighted average useful life), customer relationships of $37 million (3-year weighted average useful life), maintenance contracts of $17 million (5-year weighted average useful life), Trademarks of $2.5 million (3-year weighted average useful life), and order backlog of $7.4 million (1.5-year useful life).  The amortization for the developed technology is recorded in “Cost of revenues” for product and the amortization for the remaining intangibles is recorded in “Amortization of purchased intangibles” on the condensed consolidated statement of operations.

The Company also has an indefinite lived asset of $3 million which represents the fair value of in process research and development activities.  Once the related research and development efforts are completed, the Company will determine whether the asset will continue to be an indefinite lived asset or it has become a finite lived asset and apply the appropriate accounting accordingly.

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NOTES TO UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS

4.      Pro Forma Adjustments

The pro forma adjustments included in the unaudited pro forma condensed combined financial statements are as follows:

A.            Per the Stock Purchase Agreement signed by Extreme and Enterasys, Extreme did not acquire any cash as part of the acquisition.  Pro forma adjustments have been made to eliminate the cash and cash equivalents held by Enterasys as of the date of balance sheet presented.

B.            To record the decrease in short term investments liquidated to pay for the acquisition of Enterasys as follows:

C.            The pro forma adjustments reflect the preliminary purchase accounting fair value estimates for the net assets to be acquired and liabilities assumed.  This is an estimate based on preliminary purchase price allocation which is subject to final allocation upon completion of the valuation process.

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NOTES TO UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS

D.            Enterasys was formerly a wholly owned subsidiary of Enterprise Networks Holdings B.V. (JV Co.) which was in turn formed by a joint venture transaction between Siemens AG and Gores Group LLC. Historical Enterasys financial statements include significant related party transactions with JV Co. which have been eliminated as the Company will have no affiliation with the former owners.  The pro forma adjustments reflect the elimination of such related party transactions from the historical financial statements including affiliate receivables, affiliate notes receivable, affiliate payables, affiliate debt and related interest expense.

E.             On October 31, 2013, Extreme entered into $125 million senior secured credit facilities agreement consisting of a $65 million Term Loan and a $60 million Revolving Facility.  Both facilities mature on October 31, 2018.  Beginning on December 31, 2013, the Term Loan shall be repaid in consecutive quarterly installments in amounts as set forth by the credit facilities agreement. The draws on the Revolving Facility shall be repaid on the maturity date if not repaid before that date. The proceeds of the Term Loan were used to pay a portion of the purchase price in the acquisition of Enterasys. The Company also drew $35 million of the $60 million Revolving Facility to pay a portion of the purchase price in the acquisition of all of the issued and outstanding capital stock of Enterasys.  The pro forma adjustments reflect the incurrence of debt.

F.              The following reclassification adjustments have been made to conform Enterasys’ historical amounts to Extreme’s presentation.  The adjustments primarily relate to separately identifying current accrued warranty, reclassifying deferred costs from inventory to deferred revenue, net and deferred revenue, net of cost of sales to distributors and reclassifying deferred revenue balances out of accounts receivables and inventory to deferred revenue, net and deferred revenue, net of cost of sales to distributors.

G.            Pro forma adjustments reflect the elimination of historical Enterasys’ equity.

H.           The pro forma adjustments to depreciation and amortization reflect the net effect of the removal of the historical depreciation and amortization expense for the Enterasys assets and the addition of the new depreciation and amortization expense for property and equipment and finite-lived intangible assets acquired in the Enterasys acquisition, based on the preliminary values assigned to these assets.  The following table summarizes the pro forma adjustments to depreciation and amortization:

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NOTES TO UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS

I.                Pro forma adjustment to record the estimated stock-based compensation expense, net of estimated forfeitures, related to the unearned portion of Enterasys stock options and restricted stock units assumed in connection with the acquisition using the straight-line amortization method over the remaining vesting periods.  The estimated value of the stock options and restricted stock units assumed and converted related to the pre-combination period was immaterial and was excluded from the preliminary purchase price.

J.                Pro forma adjustment to reflect the removal of transaction costs that were incurred by Extreme and Enterasys during the three months ended September 30, 2013. These costs have been excluded since they are considered to non-recurring.

K.           The pro forma adjustments to interest expense reflect the removal of Enterasys’ historical interest expense and the addition of interest expense resulting from the new borrowings undertaken to partially finance the acquisition.  Interest expense is calculated using the actual interest rates for the periods presented.

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NOTES TO UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS

L.             The pro forma adjustments for the assumed reduction in interest income due to reduced cash and cash equivalent balances as a result of the cash consideration issued as part of the acquisition.

The effective weighted average interest rate was determined based on the actual interest recognized by the Company in its historical financial statements for the periods presented.

M.         The pro forma adjustments to deferred tax assets/(liabilities) and income tax expense, as summarized below, are due to the impact on the historical balances and provision for income taxes to reflect the establishment of a valuation allowance on the Enterasys’ deferred tax assets in the Unites States as well as a partial valuation allowance on its deferred tax assets in Brazil. As a result of the transaction, a tax sharing arrangement within the prior U.S. consolidated group was eliminated, therefore a valuation allowance in the U.S. is required as the realizability of the deferred tax assets does not meet the more likely than not threshold as the tax sharing agreement provided the majority of the positive evidence required to establish the deferred tax assets in the U.S. The establishment of the partial valuation allowance in Brazil is due to management’s assessment that as result of the transaction the business operating model of Enterasys Brazil does not support the realizability of all of the net deferred tax assets of the entity therefore only a portion of the deferred tax assets met the more likely than not threshold.

The impact of the other pro-forma adjustments to income before tax are estimated to be primarily in taxing jurisdictions where the effective tax rate is zero, therefore no pro forma adjustments to the income tax provision has been made for these items.

5.      Pro Forma Net Income per Share

The pro forma basic and diluted net income (loss) per share amounts presented in the unaudited pro forma condensed combined statements of operations are based upon the weighted average number of Extreme common shares outstanding and are adjusted for additional stock awards assumed from Enterasys stock award plans pursuant to treasury stock method as if those awards had been assumed and converted as they stood at the acquisition date as of the beginning of each period presented without consideration for any subsequent award activity such as grants, exercises and cancellations for the unaudited pro forma condensed combined statements of operations for the periods presented.  The proforma adjustment to basic shares reflects the estimated shares from the release of the restricted stock units based on the vesting terms of the grants.  The proforma adjustments to the diluted shares reflect the adjustment to the basic shares as well as the exclusion of the diluted impact of Extreme’s outstanding stock options and restricted stock awards as the pro forma adjustments result change Extreme’s

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NOTES TO UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS

income position in a combined loss position.

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