tcpdump on port 25

[Matthew Carpenter]

tcpdump -s 1600 -i eth0 -w - port 25

-s 1600 means that it will dump the whole 1500bytes Ethernet can handle
-w - means it will write the binary to STOUT (don't worry, you get 
garbage and then the text, etc...)

if -w - isn't good for you, -w <filename> then use Ethereal to dig 
deeply into the dump.


M.W. Chang wrote:

>I was debugging a program that talks to sendmail, and couldn't figured
>out the best tcpdump options to use. Here what I used:
>
>tcpdump -i eth0 -X tcp port 25
>
>However, some request/response were not shown completely.
>
>  
>