Services stop responding, but server responds to ping :(

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Posted by Apocalypse, 11-19-2007, 11:43 AM
I'm having a very odd problem with one of my Linux (CentOS) cpanel server, all the server's services (http, ssh, mail, dns, etc) stop responding but the server still responds to ping. I can't find anything wrong at all on the log files either, and the technicians that manually restart the server have told me that there is no indication of a problem on the screen. I suspected a hardware issue and had the data center techs run a hardware test on the server but everything cleared ok. This issue started a couple of weeks ago, no major upgrade or install took place when it started happening. From what i can see the halts are completely random, some times it goes for days without it happening and some times it happens just hours after the reboots. Any clues about what might be the issue? TIA, A.
Posted by activelobby4u, 11-19-2007, 11:55 AM
what does your dmesg and /var/log/messages say ??
Posted by creaws, 11-19-2007, 12:22 PM
What's the output of the command: $ telnet youserver.com 80 ? something like this? Trying x.x.x.x... telnet: Unable to connect to remote host: Connection refused or the command stays on Trying x.x.x.x... I don't think that is a hardware issue, if your sever responds to a ping. regards, creaws.
Posted by Apocalypse, 11-19-2007, 12:36 PM
I rebooted the server and is now back up, so i cant test with the telnet command, but i remember trying putty it just stay there trying to connect to ssh until i close it, no connection refused. Attached dmesg and /var/log/messsages output, note that i replaced all instances of the original servers ip addresses with 127.0.0 Thanks again. Attached Files dmesg.txt (11.1 KB, 97 views) messages.txt (89.8 KB, 154 views)
Posted by activelobby4u, 11-19-2007, 01:25 PM
There is nothing really in your logs. It just seems like you server load shot up, which made the services fail and the ssh access denied. In such a circumstance, the server would respond to ping , but the services would fail. Make sure your server is well monitored and optimized for maximum performance
Posted by Apocalypse, 11-19-2007, 01:43 PM
Its not the server load either, the server load is pretty low at all times since theres only a couple of sites on it, The server's services never come back either unless i reboot the server.
Posted by activelobby4u, 11-19-2007, 01:54 PM
whats the RAM specification of your server ?
Posted by Srv24x7, 11-19-2007, 01:57 PM
from what it looks like to be a hardware issue as far as the log says its nothing major on the server. Let me know if you still face any problems with the server.
Posted by creaws, 11-19-2007, 02:03 PM
That's generally the effect of a firewall, maybe a wrong firewall rule is blocking your inbound tcp traffic, but not ICMP, so ping works. Send us the output of command: # iptables -L if you don't want to expose your firewall rules, send it to me via pm. Best regards, Creaws.
Posted by Apocalypse, 11-19-2007, 02:36 PM
I thought that might be the issue also, and disabled APF to see if it was some sort of DoS protection clicking in and blocking everything, but a few days later got the issue again. I'll PM you the results of the "iptables -L" Thanks, A.
Posted by ISPserver, 11-19-2007, 04:54 PM
I think you need call or write to data center when server stop responding. And they look into console. Or hardware console also do not response?
Posted by Apocalypse, 11-19-2007, 05:22 PM
They told me the screen looked fine and there was nothing that might point to a hardware error all the times this has happened. I don't have access to a hardware console tho.
Posted by ISPserver, 11-19-2007, 08:02 PM
They told me the screen looked fine It's bad answer. They can try connect from server to server via http (or any other protocol). For example #wget -O - YOUR.SERVER.IP #telnet YOUR.SERVER.IP pop3 #telnet YOUR.SERVER.IP smtp If it's will show server answer then services work and you server have some filter. Also in console person can show who listen port or may be do not listen. #netstat -na |grep LISTEN I thinr only in datacenter can find a problem. Beckouse only they can acces to broken server. Or you can use remote console KVM for it.
Posted by david510, 11-19-2007, 11:42 PM
Have you made sure the services are running fine on the server and ports are listening fine? From the ssh type, netstat -lpn telnet localhost port-number
Posted by Apocalypse, 11-20-2007, 11:29 AM
Thanks a lot everyone for the responses, i suppose i need to contact the data center if this happens again to get them to check locally if the services or server is non responsive. Thanks again, A.
Posted by Darvil, 11-20-2007, 03:19 PM
are you sure the server doesn't have high load when it goes down? I've had a problem like this in the past and it turns out to be a badly coded mod for a friend's forum I was hosting.
Posted by Apocalypse, 11-29-2007, 11:56 AM
Today the server froze on me again, i contacted the datacenter and asked if the server was also unresponsive physically in case it was a network issue only, the tech replied: -- "Server was unresponsive at the console. On reboot, it auto fsck'd and corrected a dozen or so errors (mostly inode counts) on /, then reboot again." -- I can't find any error on the logs or other issue, any clues?

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