UNIX for Dummies Questions & Answers

I am using Mac OS X and my server keeps crashing every several hours or so. I have checked the log file at /var/log/system.log and the entries closest to the crash read

Code:

Mar 15 22:27:23 server servermgrd: servermgr_dns: no name available via DNS for 192.168.84.21
Mar 15 22:27:23 server servermgrd: servermgr_dns: no reverse DNS entry for server, various services may not function properly
Mar 15 22:57:23 server servermgrd: servermgr_dns: no name available via DNS for 192.168.84.21
Mar 15 22:57:23 server servermgrd: servermgr_dns: no reverse DNS entry for server, various services may not function properly

So maybe this is causing the crash? So now I am trying to figure out how to fix the reverse DNS. I ran the following command from terminal.

Code:

sudo changeip -checkhostname

it returns the following

Code:

Primary address     = 192.168.84.21

Current HostName    = server.domainwise.com

The DNS hostname is not available, please repair DNS and re-run this tool.

I dont really know how to change the DNS hostname. Can anyone help?
I tried the following:

running the command

Code:

changeip /LDAPv3/127.0.0.1 192.168.84.21 192.168.84.21 server.domainwise.com server.domainwise.com

Adding the following to /etc/hosts

Code:

192.168.84.21   server.domainwise.com

I've been googling like crazy but still found no answeres?

Hard to believe that DNS is causing the crash - if DNS isn't working, then you will probably lose your connection to the network (but the system should still be up).

First off, you have server "A" crashing. You believe it to be caused by your DNS host - is the DNS host also server "A", or is DNS actually on another server?

Second, the message shows This doesn't mean you have to change the DNS hostname - it means you have to fix it so your server "A" can find/reach the DNS hostname.

Check that your /etc/resolv.conf is set up correctly for your network. Make sure you can ping your DNS server(s) listed in /etc/resolv.conf.

And double check what is really crashing your server. Tutorial - an intro to reading MAC OS X Crash reports

The server itself lives in london i only have remote access via terminal. When i say the server crashes i mean the web sites don't reply, i can't log in via ssh and i can't ping the server from the remote address. I'm pretty sure the system is down because there are no more entries in the log past the time of crash until the hosts have restarted the server.

Server A is not configured as a DNS server i guess the DNS server is with VI (my hosting company)? I'm not really clued up on this subject. So not sure. I'm just going on what the logs say.

I will have a look at the link you posted thanks for your time.

---------- Post updated at 05:40 AM ---------- Previous update was at 05:19 AM ----------

I followed the link you posted and followed the instructions
Inside the directory /Library/Logs/CrashReporter there is only one file, it is called httpd.crash.log I looked in this and the last entry at the bottom is dated for the 6th of march, 7 days before the server started crashing. So I am assuming this isn't the problem?
Also if apache did crash i would of thought i would still be able to get in via ssh or at least still ping the server. Any ideas?

---------- Post updated at 07:23 AM ---------- Previous update was at 05:40 AM ----------

I'm starting to wonder if this is a hardware fault since the software isn't logging/reporting anything and the crashes have only just started. Everything has been working fine in the months gone by. I'm all out of ideas

Tim, is this Snow Leopard (10.6)? If so, It is not necessarily a DNS issue. Is it using dhcp? If so try and determine if the dropouts are happening exactly halfway between a lease period. Try a static IP and see if the dropouts stop. There are some issues with Snow Leopard on certain DHCP networks.

No the server is on a static IP address. It's very strange i have moved all our most important sites from the broken server (server A) to the back up server (server B). Before I did that Server A was crashing periodically every several hours. Since i have moved a lot of the sites across to server B on friday Server A hasn't crashed since. And Server B is running fine also. This has confused me even further. Could it be

1: There was to much load on server A and now i have balanced the load across the two servers.

2: There is some sort of memory leak in the php codes in some of the sites i moved. But if so wouldn't the backup server start crashing.

3: Server A just hasn't crashed yet because it is apache that is crashing and it hasn't had a chance to crash yet because there is less load. So it will take longer to crash now.

I think i will just have to leave the two servers as they are and see what happens next. It's confusing because there's no real explanation as to whats going on in the logs