hostname resolving problem in centos

dinakumar12 · 12-31-2011, 07:35 AM

Hi all,

One of our development server experienced a problem today after reboot.

The problem is server could not able to connect to both LAN and WAN.

I checked all network settings everything is fine,but still i could not able to connect to the network.

I have noticed this is /var/log/messages file

Dec 31 18:51:58 csopb automount[2706]: create_udp_client:90: hostname lookup failed: No such file or directory

Dec 31 18:52:08 csopb automount[2706]: create_tcp_client:299: hostname lookup failed: No such file or directory

Dec 31 18:52:08 csopb automount[2706]: look_mount: exports lookup failed for sf

I am clueless,continuosly i am getting these messages.Your suggestions would be helpful.

Thanks in advance,
Dinesh.

tronayne · 12-31-2011, 09:14 AM

If you were to log in as root (or use su - or sudo) and enter

Code:

hostname

in a terminal window on that server, you should see the name of the server. If you don't, chances are that you either do not have /etc/HOSTNAME or you do and it's empty.

You should carefully read the manual page (man hostname) for options.

Addition.

You may want to double-check your network configuration; if you're using fixed-IP addressing, do you have the correct IP address set for the server, netmask and gateway server. Can you ping the gateway.

If your servers are using fixed-IP do you have entries in /etc/hosts for them; e.g.,

Code:

# For loopbacking.
127.0.0.1               localhost
192.168.1.10            thisserver.domain thisserver
192.168.1.20            thatserver.domain thatserver
192.168.1.30            otherserver.domain otherserver

If you have an internal; i.e., running on your LAN, domain name system (DNS) server, do you have its address in /etc/resolv.conf; e.g.,

Code:

search com
nameserver xx.xx.xxx.x     # Local DNS server
nameserver xx.xx.xxx.x     # External DNS server

And last but not least, is the cable plugged in?

Hope this helps some.

btmiller · 01-01-2012, 12:26 AM

First thing would be to check if you can ping other hosts on the LAN by IP address. If you can ping a host by IP, but cannot resolve its name (use dig or ping to find out) then your name resolution is a problem ... check and make sure you have the right nameservers listed in /etc/resolv.conf. If you can't ping a host by IP address, there's another problem with the network. Check with the ifconfig command to make sure that your network interfaces are up and their IP(s) are set properly.