off-topic, somthing strage?

[Brett Mason]

Sorry as I know this is off topic but thought this would be a good forum to ask
this question. I am getting a bounce email such as the following:

The original message was received at Wed, 1 Aug 2001 10:19:48 +1000
 from brett@localhost

    ----- The following addresses had permanent fatal errors -----
 l4m0r@freebox.com

    ----- Transcript of session follows -----
 l4m0r@freebox.com... Deferred: mail.freebox.com.: No route to host
 Message could not be delivered for 5 days
 Message will be deleted from queue


And the actual message is:

brett
brett
eth0      Link encap:Ethernet  HWaddr 00:01:03:82:9B:AF  
           inet addr:192.168.11.54  Bcast:192.168.41.255  Mask:255.255.255.0
           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
           RX packets:69111 errors:0 dropped:0 overruns:0 frame:0
           TX packets:33600 errors:0 dropped:0 overruns:0 carrier:4
           collisions:0 txqueuelen:100 
           Interrupt:11 Base address:0xd400 

 lo        Link encap:Local Loopback  
           inet addr:127.0.0.1  Mask:255.0.0.0
           UP LOOPBACK RUNNING  MTU:16436  Metric:1
           RX packets:2145 errors:0 dropped:0 overruns:0 frame:0
           TX packets:2145 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:0 

The reason It is bouncing is because I have iptable rules on my firewall that
disallow smtp(25) out from this box. But what I want to know is what is sending
these emails. I don't think I've been hacked as this info is not to sensitive
and it has happened 2 - 3 times. I assume it is some program that is sending
this info?

any suggestions?

- Brett