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Running openSUSE 11.2 x86_64.

Here's what a nmap of my IP provides:

23/tcp open telnet
80/tcp open http
2800/tcp open unknown
8008/tcp open http

I would like to know how to view what service is causing port 2800 to be opened?

A few search engine results led me to believe that it is supposedly a port opened by a Trojan called "Theef".

If it is indeed a Trojan, what can be done to weed it out? Is my desktop's security compromised?

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up vote 0 down vote accepted

what do you see after running (as root):

nmap -sV --version-intensity 9 -p 2800 localhost

What makes you think you have a trojan? What have you been doing lately? And why are you running telnet?

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That worked. The Port's State returns as Closed. As to your questions: What makes you think you have a trojan? Curiosity. What have you been doing lately? Nothing noteworthy, except some basic coding. Why are you running telnet? Self-Vulnerability Test? :-). – Singularity Jun 5 '10 at 15:56
-sV is for identifying V-ersion numbers of any services or daemons running on the host(s). It shouldn't actually close any already open ports. Maybe something else happened.... – Felipe Alvarez Jun 6 '10 at 3:24

The -p switch to netstat should show you what processes have what ports open:

sudo netstat -p
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lsof can help also:

sudo lsof -i TCP:2800
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Tried that command, Port 80 returns results. Ports 23,2800,8008 refuse to do so. No results appear. Also tried fuser -nu tcp 2800, fuser 2800/tcp they also do not return anything. – Singularity Jun 1 '10 at 20:39
I didn't know one could do that with lsof and fuser. – Felipe Alvarez Jun 6 '10 at 3:25

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