[SOLVED] What is Required to do a NSLookup or Dig?

ECRocker · 10-15-2009, 10:01 AM

A user did something really nasty on my cluster yesterday and brought the whole thing down.

Quote:

"I was copying some stuff and I guess it was just too big for the server. I did this before and corrupted the inode registry. Oops."

Yeah, ok. So, none of my nodes are communicating correctly because now they can't pull DNS information from the master head node.

My question for LQo is simply this: What is Required to do a NSLookup or Dig?
I can ping all addresses on the subnet, but only servers by name which appear in the /etc/hosts file.

1. DNS Server / service Named started
2. Resolv.conf on the client

Code:

; generated by /sbin/dhclient-script
search masternode.local
nameserver 172.16.0.254

3. nslookup / dig packages installed
4. named.conf properly configured on the DNS server
5. named zone files
6. ?? If all of the above are correct, then what is missing ??

I thought putting the master node / dns server in my hosts file but that's not practical nor helped.

Thanks.

bhaslinux · 10-15-2009, 11:03 AM

I would start looking in this manner

1. Is your nsswitch.conf is properly configured ?
2. Is the DHCP relaying correct DNS address ?

check using
nslookup <some name in the domain> - <the dns server ip address>
this

ECRocker · 10-15-2009, 12:28 PM

1. Yes
2. Hangs, and can't talk to the DNS thru ip or fqdn

bhaslinux · 10-15-2009, 04:04 PM

Quote:

Originally Posted by ECRocker

2. Hangs, and can't talk to the DNS thru ip or fqdn

this needs to be checked. Are you able to get IP address using the DHCP server. If you are not, then try setting a static IP and see if you are able to browse network properly. If yes then it is all about troubleshooting DHCP server.

ECRocker · 10-15-2009, 06:42 PM

Yes. The DHCP server assigns an address to the node, and then xCAT (the cluster admin tool) sees the node and tells the dhcp server to reassign the ip address according to what port the ethernet cable is plugged into.
Yeah, I can browse the network by ip address, just not domain name. I can't imagine what got corrupted...

ECRocker · 10-16-2009, 11:35 AM

FIREWALL PORT 53:UDP 53:TCP !!!!!!!!!!!

The DNS Server listens for requests and responds back on those two ports.

The firewall configuration got over written, and re-opening those ports allows nslookup/dig to work properly again - as well as all my cluster software.

Heck yes.