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There seems to be a process called "cslistener" on my machine that is listening on port 9000. A scan using nmap resulted in this, where is the address of my PC.

Nmap scan report for
Host is up (0.000013s latency).
Not shown: 993 closed ports
22/tcp    open  ssh
80/tcp    open  http
139/tcp   open  netbios-ssn
443/tcp   open  https
445/tcp   open  microsoft-ds
9000/tcp  open  cslistener
10000/tcp open  snet-sensor-mgmt

What's going on here? I'm on ubuntu 12.04.

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up vote 12 down vote accepted

nmap doesn't show you which process is actually listening to some port but which service is registered with the IANA or otherwise known to use this port.

To find out which process is actually listening on that port you can use for example

 sudo fuser -v 9000/tcp
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Thanks, that command worked and it turns out Eclipse is listening on 9000. A quick search indicated that it is Xdebug for PHP. I've never actually used that tool, but I am developing a PHP application, and port 9000 is no longer used when Eclipse isn't running. – Kalle Elmér Aug 16 '12 at 21:09

It`s Sentry in default configuration -

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Most likely if you get this you are running php-fpm (PHP FastCGI Process Manager) which runs on port 9000 by default.

On my web/app servers I udpate /etc/services and change cslistener to fastcgi so a lsof -i makes more sense and another admin doesn't wonder what cslistener is.

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From what I've gathered from the internet, it might be your router's firewall, especially if you use a Buffalo router or firewall.

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