SUMMARY OF RIGHTS TO PURCHASE
SERIES A JUNIOR PARTICIPATING PREFERRED STOCK

        The Board of Directors of VIA NET.WORKS, Inc., a Delaware Corporation (the "Company"), has declared a dividend distribution of one right ("Right") for each outstanding share of Voting Common Stock, par value $.001 per share ("Voting Common Stock"), and Non-Voting Common Stock, par value $.001 per share ("Non-Voting Common Stock" and, collectively with Voting Common Stock, "Common Stock") of the Company. The distribution is payable to stockholders of record on February 12, 2004. Each Right, when exercisable, entitles the registered holder to purchase from the Company one one-thousandth of a share of Series A Junior Participating Preferred Stock ("Preferred Stock") at a price of $20 per one one-thousandth share (the "Purchase Price"), subject to adjustment. The description and terms of the Rights are set forth in a Rights Agreement (the "Rights Agreement") between the Company and Continental Stock Transfer & Trust Company, as Rights Agent (the "Rights Agent").

        Initially, the Rights will be attached to all certificates representing shares of Common Stock then outstanding, and no separate certificates evidencing the Rights will be distributed. The Rights will separate from the Common Stock and a distribution of Rights Certificates (as defined below) will occur upon the earlier to occur of (i) 10 days following a public announcement that a person or group of affiliated or associated persons (an "Acquiring Person") has acquired, or obtained the right to acquire, beneficial ownership of 15% or more of the outstanding shares of Common Stock (the "Stock Acquisition Date") or (ii) 10 business days (or such later date as the Board of Directors of the Company may determine) following the commencement of, or the first public announcement of the intention to commence, a tender offer or exchange offer the consummation of which would result in the beneficial ownership by a person of 15% or more of the outstanding shares of Common Stock (the earlier of such dates being called the "Distribution Date").

        Until the Distribution Date, (i) the Rights will be evidenced by the Common Stock certificates, and will be transferred with and only with the Common Stock certificates, (ii) new Common Stock certificates issued after February 12, 2004 upon transfer or new issuance of the Common Stock will contain a notation incorporating the Rights Agreement by reference, and (iii) the surrender for transfer of any certificates for Common Stock outstanding will also constitute the transfer of the Rights associated with the Common Stock represented by such certificate.

        The Rights are not exercisable until the occurrence of a Distribution Date and will expire at the close of business on January 28, 2014, unless earlier redeemed or exchanged by the Company as described below.

        As soon as practicable following the Distribution Date, separate certificates evidencing the Rights ("Rights Certificates") will be mailed to holders of record of the Common Stock as of the close of business on the Distribution Date and, thereafter, the separate Rights Certificates alone will evidence the Rights. Except as otherwise determined by the Board of Directors of the Company, only shares of Common Stock issued prior to the Distribution Date will be issued with Rights.

        In the event that a Person becomes the beneficial owner of 15% or more of the then outstanding shares of Common Stock, each holder of a Right will, after the end of a redemption period referred to below, have the right to exercise the Right by purchasing, for an amount equal to the Purchase Price, Voting Common Stock (or, in certain circumstances, cash, property or other securities of the Company) having a value equal to two times such amount. Notwithstanding any of the foregoing, following the occurrence of the events set forth in this paragraph, all Rights that are, or (under certain circumstances specified in the Rights Agreement) were, beneficially owned by any Acquiring Person will be null and void. However, Rights are not exercisable following the occurrence of the events set forth above until such time as the Rights are no longer redeemable by the Company as set forth below.

        For example, at a Purchase Price of $20 per Right, each Right not owned by an Acquiring Person (or by certain related parties) following an event set forth in the preceding paragraph would entitle its

holder to purchase $40 worth of Voting Common Stock (or other consideration, as noted above) for $20.

        In the event that, at any time following the Stock Acquisition Date, (i) the Company is acquired in a merger or other business combination transaction, or (ii) 50% or more of the Company's assets or earning power is sold or transferred, each holder of a Right (except Rights which previously have been voided as set forth above) shall, after the expiration of the redemption period referred to below, have the right to receive, upon exercise, common stock of the acquiring company having a value equal to two times the Purchase Price of the Right (e.g., common stock of the acquiring company having a value of $40 for the $20 Purchase Price).

        At any time after a person or group of affiliated or associated persons becomes an Acquiring Person and prior to the acquisition by such person or group of 50% or more of the outstanding Common Stock, the Board of Directors of the Company may exchange the Rights (other than Rights owned by such person or group which have become void), in whole or in part, at an exchange ratio of one share of Voting Common Stock per each outstanding Right or, in certain circumstances, other equity securities of the Company which are deemed by the Board of Directors of the Company to have the same value as shares of Voting Common Stock, subject to adjustment.

        In general, the Board of Directors of the Company, may cause the Company to redeem the Rights in whole, but not in part, at any time during the period commencing on January 29, 2004 and ending on the tenth day following the Stock Acquisition Date (the "Redemption Period") at a price of $.001 per Right (payable in cash, Common Stock or other consideration deemed appropriate by the Board of Directors of the Company). Under certain circumstances set forth in the Rights Agreement, the decision to redeem the Rights will require the concurrence of the two-thirds of Directors. After the Redemption Period has expired, the Company's right of redemption may be reinstated if an Acquiring Person reduces his beneficial ownership to 10% or less of the outstanding shares of Common Stock in a transaction or series of transactions not involving the Company and there are no other Acquiring Persons. Immediately upon the action of the Board of Directors of the Company ordering redemption of the Rights, the Rights will terminate and the only right of the holders of Rights will be to receive the $.001 redemption price.

        Until a Right is exercised, the holder thereof, as such, will have no rights as a stockholder of the Company, including, without limitation, the right to vote or to receive dividends. While the distribution of the Rights will not be subject to federal taxation to stockholders or to the Company, stockholders may, depending upon the circumstances, recognize taxable income in the event that the Rights become exercisable for Common Stock (or other consideration) of the Company or for common stock of the acquiring company as set forth above.

*    *    *

        A copy of the Rights Agreement has been filed with the Securities and Exchange Commission as an Exhibit to a Current Report on Form 8-K. A copy of the Rights Agreement is available free of charge from the Company. This summary description of the Rights does not purport to be complete and is qualified in its entirety by reference to the Rights Agreement.

2

QuickLinks