Re: TCPReplay problem

[Graeme Connell <gconnell () middlebury edu>]

> Can we direct tcpreplay to send packets to another machine?

Yes.

> If so what is the command for that.

You can use tcpreplay to send packets to another machine.  You have to 
do a bit of work, though.  First, you can change the source and 
destination IP addresses for all packets with the '-e' flag.  So calling

./tcpreplay -i eth0 -e 1.1.1.1:2.2.2.2 test.pcap

will send all packets in 'test.pcap' through interface 'eth0', rewriting 
the source IP for all packets to '1.1.1.1' and the destination IP to 
'2.2.2.2'.  However, you should also change the layer 2 source and 
destination MAC, which can be done with the '-I' and '-k' flags.

./tcpreplay -i eth0 -e 1.1.1.1:2.2.2.2 test.pcap -I 11:11:11:11:11:11 -k 
22:22:22:22:22:22

This rewrites the source MAC to '22:22:22:22:22:22' and the destination 
MAC to '11:11:11:11:11:11'.  Of course, if the destination computer is 
in your subnet, the dest MAC should be its MAC, otherwise, it should be 
the MAC of your gateway.  The source MAC should be your compy's, but 
this shouldn't really be necessary.

So, to recap, get the IP of the machine you want to send to, then the 
MAC of that machine (if it's in your subnet) or your gateway (if it's 
not), then place that info into the tcpreplay call, and you should be 
able to resend captured packet data to another computer.

                --Graeme Connell


------------------------------------------------------------------------------
This List Sponsored by: Cenzic

Concerned about Web Application Security? 
Why not go with the #1 solution - Cenzic, the only one to win the Analyst's 
Choice Award from eWeek. As attacks through web applications continue to rise, 
you need to proactively protect your applications from hackers. Cenzic has the 
most comprehensive solutions to meet your application security penetration 
testing and vulnerability management needs. You have an option to go with a 
managed service (Cenzic ClickToSecure) or an enterprise software 
(Cenzic Hailstorm). Download FREE whitepaper on how a managed service can 
help you: http://www.cenzic.com/news_events/wpappsec.php 
And, now for a limited time we can do a FREE audit for you to confirm your 
results from other product. Contact us at request () cenzic com for details.
------------------------------------------------------------------------------