The issue is that normally, ethernet is limited to 1514 byte packets (14 bytes for the ethernet header + 1500 bytes of data). Packets which are larger are known as "jumbo packets". This is called the MTU- maximum transmision unit.
Anyways, you can generally increase the MTU by using ifconfig. That will allow tcpreplay to send these larger packets. -- Aaron Turner http://synfin.net/ http://tcpreplay.synfin.net/ - Pcap editing and replay tools for Unix & Windows They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety. -- Benjamin Franklin On Fri, Nov 28, 2008 at 7:13 AM, Violette Moulin <[EMAIL PROTECTED]> wrote: > Hi, > > I'm trying to capture and replay multicast traffic, and I've a problem > with big packets. > > I send UDP traffic from PC1 to PC2, and capture then on PC1 : > $ tcpdump -w myCapture.pcap -s0 -i eth2 dst port 7767 > > Then I replay it on PC1 : > $ tcpreplay --intf1=eth2 myCapture.pcap > > The traffics seems arrive, as shows me tcpdump on PC2: > $ tcpdump -n -s0 -i eth2 dst port 7767 > tcpdump: verbose output suppressed, use -v or -vv for full protocol decode > listening on eth2, link-type EN10MB (Ethernet), capture size 65535 bytes > 15:58:36.938789 IP 192.168.2.42.40720 > 224.0.0.1.7767: UDP, length 9 > 15:58:37.939454 IP 192.168.2.42.40720 > 224.0.0.1.7767: UDP, length 2009 > 15:58:38.940371 IP 192.168.2.42.40720 > 224.0.0.1.7767: UDP, length 2009 > 15:58:39.941367 IP 192.168.2.42.40720 > 224.0.0.1.7767: UDP, length 2009 > ... > > On PC2, I have a simple application which receive multicast packets. > When I directly send traffic from PC1 to PC2, my application receive > all the packets, but when I replay the same traffic with tcpreplay, it > only receive the first packet, which is smaller. > I tryed to send only small packets, and it works. > > Is there any option to modify the packets size which are recorded by > tcpdump (I used the -s0 option)? > Did I make a mistake in my tcpdump or tcpreplay command? ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Tcpreplay-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/tcpreplay-users Support Information: http://tcpreplay.synfin.net/trac/wiki/Support
