[NTLUG:Discuss] Have I been hacked?

[Bobby Sanders]

On April 5th LogWatch shows:

Connections:
   Service in.telnetd:
      216.139.215.3: 1 Time(s)

On April 9th LogWatch shows:

 --------------------- sendmail Begin ------------------------ 

676590 bytes transferred
96 messages sent

**Unmatched Entries**

gethostbyaddr(206.50.48.104) failed: 2 

 ---------------------- sendmail End ------------------------- 

I've never sent 96 messages at once on purpose.  (This machine is not
on a local area network.)

Have I been hacked?  If so, how do I locate and stop it.  I don't need
telnet services into the machine but have left the RH 6.2 in its
default configuration.  I have always felt relatively safe since my ISP
assigns dynamic dotted quads.

Guess I need to change my attitude!  :(  bummer.

As usual, all help will be greatly appreciated.

Bobby