Server Up, Websites Won't Resolve

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#1 Thu, 08/25/2011 - 11:52
UWF

Server Up, Websites Won't Resolve

I woke up this morning to find all of my websites down on one of my Virtualmin servers. I have about 7 domains hosted on it and they are all down but the server is up as long as I don't try connecting with domain names. I haven't changed anything since last night except adding a cron job to build a sitemap on one of my sites. I tried intodns and it finds a bunch of problems but I don't know how they were caused or how to fix them.

http://www.intodns.com/urbanwarezforum.com

Thu, 08/25/2011 - 12:20
andreychek

Howdy,

It looks like the nameservers for your domain aren't responding.

Is it your server that's acting as the nameserver for that domain? If so, you may want to make sure that BIND is running, and that port 53 UDP isn't being blocked by a firewall.

-Eric

Thu, 08/25/2011 - 12:27
UWF

Hi. Yes the server is acting as my nameserver. I tried rebooting the whole server, no luck, how can I check the firewall?

Thu, 08/25/2011 - 12:34
andreychek

Howdy,

Well, the first step is to make sure BIND is actually running... if there were some sort of syntax error in the BIND config, that could cause problems with it starting up.

What output do you receive if you run this command from the command line:

netstat -an | grep :53

Also, you can see if there's a firewall running on your server with this command:

iptables -L -n

Is your server behind a NAT router of some sort? If so, and something weren't working with the port forwarding, that could cause the problem you're seeing.

-Eric

Thu, 08/25/2011 - 14:05
UWF

I don't receive any output from that command. Just enters and the command line comes up again.

This comes up when I check for a firewall.

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 root@srv:~#

And I'm not really sure if it's behind NAT or a router.

Thanks.

Thu, 08/25/2011 - 14:16
andreychek

If that first command doesn't produce any output, that suggests that BIND isn't running.

The next step is to figure out what happens if we try to manually launch it.

What distro/version is it that you're using?

-Eric

Thu, 08/25/2011 - 14:17
UWF

I am using Debian 6 64bit.

Thu, 08/25/2011 - 14:21
andreychek

Great... what output do you get if you run this command:

/etc/init.d/bind9 start

Once you do that, does this command produce any output:

netstat -an | grep :53

If not -- you may need to review the logs to see what's going on. BIND errors/warnings would appear in /var/log/syslog.

-Eric

Thu, 08/25/2011 - 14:25
UWF

The first command gives me Starting domain name service...: bind9. Second command:

tcp 0 0 188.95.52.196:53 0.0.0.0:* LISTEN tcp 0 0 188.95.52.170:53 0.0.0.0:* LISTEN tcp 0 0 127.0.0.1:53 0.0.0.0:* LISTEN tcp6 0 0 :::53 :::* LISTEN udp 0 0 188.95.52.196:53 0.0.0.0:* udp 0 0 188.95.52.170:53 0.0.0.0:* udp 0 0 127.0.0.1:53 0.0.0.0:* udp6 0 0 :::53 :::*

Thanks.

Thu, 08/25/2011 - 14:36
andreychek

That looks good, it appears to be listening on port 53 now. I'm also able to do a lookup on your domain now.

It sounds like you may want to verify that BIND is set to start on bootup. You can verify that in Webmin -> System -> Bootup and Shutdown.

-Eric

Thu, 08/25/2011 - 16:06
UWF

Ok, thanks a lot, I'll take a look at that. Although when I logged into Virtualmin it said BIND was running.

Thu, 08/25/2011 - 16:07
UWF

Strangely it was off on boot, thanks.

Thu, 08/25/2011 - 16:22
UWF

Do you think rewriting my crontab from a txt file would have anything to do with that? I copied all the old cron entries to it.

Thu, 08/25/2011 - 16:26
andreychek

Do you think rewriting my crontab from a txt file would have anything to do with that?

Nope! BIND and those cron entries aren't related, modifying cron wouldn't effect whether BIND is running.

-Eric

Thu, 08/25/2011 - 16:27
UWF

Do you think rewriting my crontab from a txt file would have anything to do with that? I copied all the old cron entries to it.

Thu, 08/25/2011 - 16:27
UWF

Ok thank you, you're so much help.

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