Is there any way to figure out what service is answering on what port for a certain machine? I think the wrong service is answering on the port 80 for HTTP requests. I get connection refused for http://toothlessrebel.org, which should be a domain hosted on port 80 of that machine. I know the domain points to the right device, because all other services on the machine work excellently. TeamSpeaks servers respond on 4 different ports, and TS TCP and WedAdmin services are functional. There are two domains listening on port 80, the default, brandontechclub.org and toothlessrebel.org, which both worked previously. After adding postfix for mail delivery I get connections refused those URLs. Also, e-mails do not get delivered. There is a temporary fix in that if I reset the router forwarding the ports it will function perfectly for some time, but without any known interference both e-mail and port 80 HTTP will be refused. Any ideas? Anything I can use to come up with some ideas? The machine is set up in the LAN DMZ so should not have port issues.

Is the response when opening a telnet connection to port 25 on the machine, using "telnet toothlessrebel.org 25".

Telnet to port 80. Using "telnet toothlessrebel.org 80".

SSH to port 80, using "ssh -p 80 toothlessrebel.org".

It really just looks like port 80 is being blocked somewhere... ISP perhaps?
I don't think so, because I have used port 80 before by putting the machine in the DMZ and it worked.

Try using nmap localhost

Starting nmap 3.45 ( http://www.insecure.org/nmap/ ) at 2006-05-11 16:33 EDT
Interesting ports on localhost (127.0.0.1):
(The 1641 ports scanned but not shown below are in state: closed)
PORT STATE SERVICE
21/tcp open ftp
22/tcp open ssh
25/tcp open smtp
37/tcp open time
53/tcp open domain
79/tcp open finger
80/tcp open http
111/tcp open rpcbind
113/tcp open auth
548/tcp open afpovertcp
631/tcp open ipp
953/tcp open rndc
3306/tcp open mysql
5000/tcp open UPnP
6001/tcp open X11:1
6002/tcp open X11:2

Nmap run completed -- 1 IP address (1 host up) scanned in 0.599 seconds

Interestingly enough, 25 is smtp and 80 is http as would normally be expected.

Anyway I can track down the breakdown?

Thanks

When the site goes down, can you still get there from the local machine? Is the server at a static IP (if not can you verify it still has an IP when the server goes down)? Perhaps your router is doing something funky with the firewall???

I'm not an expert, so I'm just grabbing at straws here... I feel like there are some tools (nagios? netstat? traceroute?) that may be able to help you trace the route of your request.

1. Yes, local machine and local network will access the site.

2. It is not a static IP but the IP can be verified because all other services at the domain and hence IP function.

3. Router is most likely my culprit. Looking for toola to see why.

I am grabbing at straws too. All outgoing traffic is fine.

You do not mention what your router is, and I agree that looks like the problem ... but I still question the failure if it occurred after installing postfix. If you stop the postfix daemon and reset your router does your system still fail? If so, I would really look at the router.

When all else fails, do a full reset (reset to factory) of the router and then setup the routing rules again ... or just look and make sure you do not have port translation enabled and set to the wrong port.

If i "Apply Changes" without changing anything it reboots the router, which corrects the problem. It's a netgear router... model to come.