RE: how to trace what is accessing the nic ?

["Simon Li" <simon.li () themachineroom co uk>]

> -----Original Message-----
> From: Bonmariage, Serge [mailto:serge.bonmariage () GETRONICS com] 
> Sent: 22 April 2005 14:45
> To: security-basics () securityfocus com
> Subject: how to trace what is accessing the nic ?
>
> Hi everyone,
>
> There is happening something very strange on one of our Linux 
> SMTP gateway.
> We've recently discovered that it is sending some strange TCP 
> packets to always the same private address.
>
> [root@server1 root]# tcpdump -i eth0
> tcpdump: listening on eth0
> 14:29:50.226313 server1.mysite.com.59806 > 192.168.234.236.5860: S
> 312929991:312929991(0) win 5840 <mss 1460,sackOK,timestamp 
> 1658853393 0,nop,wscale 0> (DF) 14:29:53.222040 
> server1.mysite.com.59806 > 192.168.234.236.5860: S
> 312929991:312929991(0) win 5840 <mss 1460,sackOK,timestamp 
> 1658853693 0,nop,wscale 0> (DF)
> 14:29:59.222028 server1.mysite.com.59806 > 192.168.234.236.5860: S
> 312929991:312929991(0) win 5840 <mss 1460,sackOK,timestamp 
> 1658854293 0,nop,wscale 0> (DF)
>
> However we don't detect any other abnormal acvtivity.
>
> The question is quite basic but is there a way to trace which 
> process is trying to send these packets?

If you can catch the process in the middle of it sending some packets,
try running
netstat --inet -nap
as root. I think this gives you a list of all processes with network
sockets open, together with the process id and name.

Simon


This e-mail message (including its attachments) is private, is intended for the recipient named in it and may contain 
material which is confidential and privileged. 
No-one other than the named recipient may read, copy, rely on, redirect, save or alter the message or any part of it or 
any attachment to it in any way. 
VMS does not accept legal responsibility for the contents of this message.
Any views or opinions presented are solely those of the author and do not represent those of VMS unless otherwise 
specifically stated. 
While reasonable effort has been made to ensure this message is free of viruses, opening and using this message is at 
the risk of the recipient.