tcpdump with IP aliasing

[Jesus M. Salvo Jr.]

I have an ethernet card with 2 ip addresses. tcpdump seems to listen
only to the network address of the first IP address assigned to the
card, but does not listen to network address of the 2nd IP address
assigned.

... but I really just want to listen on the network address of the 2nd
ip address.

I guess I could just remove all IP addresses and add just that one, run
tcpdump, and reset all the IP aliases again.

John Salvo

--
Java classes for graph manipulation:
http://homepages.ihug.com.au/~jmsalvo/graph

[Jens Mander]

First - sorry i can't help you with your problem, but obviously you can help
with mine.
I want to use a linux computer for routing and masquerading. Could you
please tell me how you've made your ethernet card listen to more than one
address?
It's probably just a laugh for you, but i am not that far experienced with
linux.
Thanks in advance

Jens

Jesus M. Salvo Jr. <jms...@ihug.com.au> schrieb in im Newsbeitrag:
383D3310...@ihug.com.au...

[Gilbert Ramirez]

Nearly 943621264 seconds after the Epoch, "Jesus M. Salvo Jr." <jms...@ihug.com.au> wrote:
>
> I have an ethernet card with 2 ip addresses. tcpdump seems to listen
> only to the network address of the first IP address assigned to the
> card, but does not listen to network address of the 2nd IP address
> assigned.

tcpdump has an "-i" option to select which interface, not IP address, to listen on.
If you run ifconfig (perhaps /sbin/ifconfig or /usr/sbin/ifconfig), you'll see
the names of your interfaces, both the physical ethernet interface and your
virtual one. Most likely the physical one is eth0 and the virtual one is eth0:1

Have you tried "tcpdump -i eth0:1" I'm not sure if it will work or not, but
that's what I'd try.

--gilbert