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I am renting a VPS with Debian installed running JBoss AS6 for my web app. I recently had some problems with my DNS hosts as they messed up the A-records for my domain which caused some new A-records to be added by mistake.

The DNS problem is now sorted and the domain is working ok, however I noticed that the web server no longer responds via direct IP or hostname in a web browser (although it pings ok and I can SSH in using the hostname ok).

UPDATE:

I am using rinetd to forward traffic from 80 to port 8080, see below the output from the rinetd log (masked the IP addresses)

Webpage requested using www.mydomain.com

16/Jan/2013:11:04:15    92.23.40.45 77.**.6.32  80  77.**.6.32  8080    4923    6196    done-local-closed

Webpage requested using IP, hostname or naked domain (without www)

16/Jan/2013:11:08:21    92.23.40.45 77.**.6.32  80  77.**.6.32  8080    0   0   done-remote-closed

This suggests to me that the requests are being received by the server, but rinetd logs show no data sent / received from the client? Does this mean the request is being blocked?

UPDATE AGAIN:

As per answer below I have checked IP Tables for firewall rules and output is

Chain INPUT (policy ACCEPT)
target     prot opt source               destination         

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination    

Which seems to indicate there are no additional rules setup?

I am still thinking this is an issue with my DNS host as it was working before they cocked up the A-records, but they have insisted the mappings are correct, is there a way to verify this?

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2 Answers 2

If you can join it with some protocols (ICMP/SSH), but not with HTTP, it seems like a firewall is blocking it (I think you thought about it before posting here). Double check that there is no software or hardware firewall! If you try to test the port of the machine, what does it returns? Type this on you client command line: "nc -z 80 ; echo $?" If there is no reply of the server for a while although the same command with 22 instead of 80, works, then, it confirms that you have something dropping the packets! If the above commands returns 1, then, it seems the port is closed from outside. Maybe the web server does not listen on port 80 anymore. And if you receive a 0, then that means the port can be reach (then everything should be ok).

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Hi Guillaume, Thanks for the response, I tried this and got "no port[s] to connect to 1", but I also got the same response on the other server which DOES respond on 80..?? (both servers are on the same LAN)...any ideas? –  DaveB Nov 25 '12 at 12:14
    
Sorry mate, my command was incomplete, here the real one: "nc -z <IP OF THE SERVER> 80 ; echo $?" –  Guillaume Fenollar Nov 27 '12 at 17:37
    
No probs, both servers responded with 0, does this indicate that it is listening on 80, but something preventing the reverse DNS lookup? –  DaveB Nov 27 '12 at 17:46
    
Then maybe your application is completely stuck? –  Guillaume Fenollar Nov 28 '12 at 14:39
    
My application is working fine, I can access from the domain, but I cant access via IP address directly, maybe you are right about the firewall, if I can prove this I will mark you answer correct...thanks for the suggestions –  DaveB Dec 1 '12 at 17:33
up vote 0 down vote accepted

The cause of this probelm was actually due to the Application Server (JBoss AS 6) not being configured correctly, I needed an extra tag entry in the server.xml file for the naked domain

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