🚀 go-pugleaf

In aus.computers.linux on Tue, 13 Dec 2011 05:49:37 +1100
Polly the Parrott <flatulantdingo@deadspam.com> wrote:
> Running Zenmap, shows
>
> "4001/tcp open http-proxy Squid webproxy"
>
> I need that port for another service.
>
> Not using squid, so I did a complete removal in Synaptic and rebooted.
>
> Zenmap still gave the same above results.
>
> Question is, how can I close that port so that it is available to the other 
> service?
>

By finding out what *really* has it open!

(Yes, this crusty old unix admin does not trust gui tools...)


sudo lsof -i -P 

what this does is give you the power of root (the sudo bit) to have
lsof (a very useful tool) list all the internet connections (the -i)
using port numbers (the -P)

(when sudo asks for a password it wants your password)

So have a look at that, looking for 4001 in the last column, the one
after TCP/UDP.
 (you can use grep to make it easy, sudo lsof -o -P | grep 4001 )

eg, on my box what's using port 5900 is this:

x11vnc     2635 zebee    9u  IPv4    16167      0t0  TCP *:5900 (LISTEN)

so that's the program x11vnc with the PID (process id) 2635 

if I do a process listing:
[zebee@hp Default]$ ps -ef | grep 2635
zebee     2635  2445  0 Nov11 ?        00:39:19 /usr/bin/x11vnc -display :0


Now.. using grep strips the headers but I know that the first number
is the PID of x11vnc and the 2nd is its parent

[zebee@hp Default]$ ps -ef | grep 2445
zebee     2445     1  0 Nov11 ?        00:00:00 kdeinit4: kdeinit4 Running...

Right... so x11vnc is run by kdeinit, so it's in my startup items.  

So use lsof -i -P to see what's using  port 4001, then the process
listing and grep to see just what's going on.

Zebee