I am trying to open port 3000 on Ubuntu 12.04, cause I have a web server listening there. I'm a bit out of my confort zone here, and spent many hours trying to solve the problem without success.

Port seems to be open in the firewall :

$> sudo ufw status

Status: active



To                         Action      From

--                         ------      ----

...

3000/tcp                   ALLOW       Anywhere

3000/tcp                   ALLOW       Anywhere (v6)

The server is listening alright on that port :

$> netstat -an | grep "LISTEN "

...

tcp        0      0 127.0.0.1:3000          0.0.0.0:*               LISTEN     

...

And I can even wget alright the index page :

$> wget localhost:3000

Connecting to localhost (localhost)|127.0.0.1|:3000... connected.

HTTP request sent, awaiting response... 200 OK

And the received file contains what I expect ("hello world" :).

However, when trying from another computer, or if I wget mydomain.com:3000 I get "connection refused", and nmap tells me that the port is not open :

$> nmap -A -T4 mydomain.com

Host is up (0.00032s latency).

...

Not shown: 999 closed ports

PORT   STATE SERVICE VERSION

22/tcp open  ssh     OpenSSH 5.9p1 Debian 5ubuntu1 (protocol 2.0)

...

Service Info: OS: Linux

Any idea what I should try next ???

EDIT

Here's what traceroute gives :

$> traceroute mydomain.com

traceroute to mydomain.com (176.31.x.x), 30 hops max, 60 byte packets

 1  mydomain.com (176.31.x.x)  0.034 ms  0.013 ms  0.010 ms