1. A method for performing by a proxy discovery of a maximum transmission unit of a path between a client and a server, the method comprising: (a) increasing, by a first proxy, a size of a path maximum transmission unit (PMTU) by a predetermined amount for transmitting network packets between a client and a server via the first proxy; (b) repacketizing, by the first proxy, network packets received from the client for transmission to the server into packet sizes in accordance with the size of the PMTU; (c) determining, by the first proxy, a first network packet of the repacketized network packets with a round trip time greater than a previous round trip time for networks packets transmitted to the server; and (d) increasing, by the first proxy, the size of the PMTU by the predetermined amount responsive to receiving an acknowledgement for the first network packet without a fragmentation indication.