Find out what's using port 80 on ubuntu [closed]

Question

I'm having trouble running a service on port 80 since it seems to be already in use by another program. Problem is, using nestat -lpn | grep :80 (or variants of this command) does not show any process using port 80.

I'm runnning Ubuntu 12.04.1 LTS, on an unknown VM provided by my school. Supposedly they do not impose any kind of restrictions, so the server is considered to behave like a physical box connected directly to the internet.

As I've already stated, greping netstat for port 80 does not produce any output even as sudo. Just to make sure its working right greping for port 22 brings up sshd. Ports 8080 and 443 also appear to be in use but don't show up on netstat.

Any help would be greatly appreciated.

Answer 1

Does your error indicate that it's really in use, or are you just not able to open a socket?

Just an idea, but are you trying to run it as root? Port 80 is kinda special, so you might give it a try. In fact all ports under 1024 are protected to be opened only by root.

Welcome to SO :)