On 7/15/07, Torsten Curdt <[EMAIL PROTECTED]> wrote: > I send one UDP packet from a client to a server machine. I capture it > on the server with > > tcpdump -i eth0 -s0 -p -n dst port 32333 -w sample.pcap > > Then I start tcpdump on the server just to see what's coming in > > tcpdump -i eth0 -p -n -v dst port 32333 > > Now when I am sending the UDP packet from the client machine. I see > the proper entry printed on stdout from tcpdump, the server receives > the packet and all is good. > > 00:50:27.638482 IP (tos 0x0, ttl 51, id 62640, offset 0, flags > [none], proto: UDP (17), length: 171) 84.58.12.57.31959 > > 89.241.0.139.32333: UDP, length 143 > > When I replay the captured packet on the server though > > tcpreplay -i eth0 sample.pcap > > I can see it printed out on tcpdump but the server is not receiving > the packet. > > 00:50:23.250751 IP (tos 0x0, ttl 51, id 174, offset 0, flags > [none], proto: UDP (17), length: 171) 84.58.12.57.32148 > > 89.241.0.139.32333: UDP, length 143 > > I assume that means that the kernel basically is dropping the packet. > But as this time the MAC address does not need to be changed I am not > quite sure why the server does not see the packet.
The host that is running tcpreplay will not process outgoing packets. This is because tcpreplay uses low level sockets to write the packet which bypasses the IP stack of the host. Your choices are: 1) Replay the traffic from a different host 2) Replay the traffic on the same host, but from a different interface (eth1 for example) Regards, Aaron -- Aaron Turner http://synfin.net/ http://tcpreplay.synfin.net/ - Pcap editing & replay tools for Unix ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Tcpreplay-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/tcpreplay-users
