Tcpreplay

Inspect the PCAP before replaying it, select the test interface and choose original timing, a fixed packet/bit rate or a speed multiplier. tcprewrite can retarget addresses and ports first; tcpprep can prepare a two-interface client/server test. Replay requires raw-socket access and sends real captured frames, so use an isolated, authorized test path. Ordinary tcpreplay does not negotiate a TCP session or wait for a useful response; tcpliveplay is a separate full-stack tool. Its successful-packet counter means frames were handed to the interface, not received downstream. Check capture truncation as well, since only saved bytes can be replayed. The suite is GPLv3 software.