Wow! Got it working. From one linux machine I can replay a pcap through a router.
I had to do two things that were not mentioned in the tcpreplay documenation: * Use the command-line option "--fixcsum" when doing "tcprewrite". The router may throw away packets for having incorrect checksums. * Turn off the router's firewall, so that it accepts traffic both directions. Mike On Thu, Apr 3, 2014 at 6:45 PM, Fred Klassen <[email protected]> wrote: > I think OpenWRT is good to go. I have used it before for VoIP calls and > never had a problem. Changing port numbers is not a problem as long as it > is predictable. For example, if port 5000 source is always translated to > 8000, not a problem. If the translation is unpredictable, then you have a > problem. > > Only older routers are affected. I had an old FreeBSD based router that > didn't work, but we got rid of it a few years ago. > > Fred. > > From: Mike A <[email protected]> > Reply-To: Main forum for tcpreplay <[email protected]> > Date: Thursday, April 3, 2014 at 1:22 PM > > To: Main forum for tcpreplay <[email protected]> > Subject: Re: [Tcpreplay-users] Passing Traffic Through a Router using one > Linux machine? > > I'm actually using an OpenWrt router - perhaps there is a way to turn > off or simplify the NAT so that it does not change port numbers? > > Mike > > > On Thu, Apr 3, 2014 at 9:44 AM, Fred Klassen <[email protected]> wrote: > >> If it was a router without NAT you could make this work provided that >> your hardware was identical to IP addresses/MAC addresses in the pcap file. >> If not, you will have to use tcprewrite/tcpprep to make it so. >> >> With NAT there is an extra complication. When a connection is >> established, NAT will translate the source port number. The algorithm is >> different from one NAT to the next. What is difficult is if the translated >> source port is completely random with no relation to the original source >> port. Luckily those NATs are going by the wayside because they break TURN >> servers, and thereby break direct peer-to-peer VoIP calls (VoIP proxy >> required). >> >> Provided the capture was done on the same NAT with the same source port >> translation algorithm, and the same care is taken to ensure that the >> addresses match the hardware, and the NAT supports TURN, you should be OK. >> >> Fred. >> >> From: Mike A <[email protected]> >> Reply-To: Main forum for tcpreplay <[email protected] >> > >> Date: Wednesday, April 2, 2014 at 7:11 PM >> To: "[email protected]" < >> [email protected]> >> Subject: [Tcpreplay-users] Passing Traffic Through a Router using one >> Linux machine? >> >> Hi, >> >> I'm running tcpreplay 4.0.4 on Ubuntu Linux 12. I've read the usage >> examples (http://tcpreplay.synfin.net/wiki/usage) and followed along. >> I'm trying to replay a single-stream (one 5-tuple) pcap so that packets go >> through a router. >> >> My hardware setup is involves one Linux machine (with eth0 and eth1) >> and one router (which does NAT): >> >> eth0 <-> LAN (router) WAN <-> eth1 >> 192.168.0.1 <-> 192.168.0.2 (router) 10.0.0.2 <-> 10.0.0.1 >> >> * Will this physical setup work? Or are there common pitfalls or >> mistakes? >> * For packets that have src IP 192.168.0.1 and dst IP 10.0.0.1 (both on >> the linux machine), will the Linux OS short-circuit and simply pass packets >> internally (and not actually send it out to the router?)? >> >> >> If I can get tcpreplay to actually send packets from a pcap through a >> router I will donate $ to whoever or whatever, because this will be the >> most useful tool. It's something I have needed for such a long time, and >> will get used a lot. >> >> Thanks ahead for any help, >> Mike >> >> >> ------------------------------------------------------------------------------ >> >> _______________________________________________ >> Tcpreplay-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/tcpreplay-users >> Support Information: http://tcpreplay.synfin.net/trac/wiki/Support >> > > > > ------------------------------------------------------------------------------ > > _______________________________________________ > Tcpreplay-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/tcpreplay-users > Support Information: http://tcpreplay.synfin.net/trac/wiki/Support >
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