Diagnosing Hostname Problems
To set the hostname locally
If you want the appliance to use the same hostname for all NICs, set the hostname in the /etc/sysconfig/network file.
If you want to use different hostnames for individual NICs, set the hostname in the /etc/sysconfig/network-scripts/ifcfg-ethX file. X is the number of the interface, for example eth0.
Add the following line to the file:
where london01 is the new hostname.
If you do not have a DNS entry for the host, or you require a failsafe when DNS is unavailable, enter the hostname and FQDN in the etc/hosts file. Use the appliance IP address if it is unlikely to change, or a loopback IP address other than 127.0.0.1 (which can interfere with the resolution of localhost and localdomain.
The following example uses london01 as the hostname, london.com as the domain name, and 192.168.0.100 as the IP address. Add only one of the example entries.
::1 localhost6.localdomain6 localhost6
### Enter either this line if the IP address is known
192.168.0.100 london01.london.com london01
### Or this line to use a loopback address
127.0.0.2 london01.london.com london01
The following example uses the same host and domain names as above and shows commands to enter to ensure that the hostname is set correctly:
london01
[tideway@london01 ~]$ hostname --domain
london.com
[tideway@london01 ~]$ hostname --fqdn
london01.london.com
[tideway@london01 ~]$ ping `hostname`
PING london01 (192.168.0.100) 56(84) bytes of data.
64 bytes from london01 (192.168.0.100): icmp_seq=1 ttl=64 time=0.050 ms
64 bytes from london01 (192.168.0.100): icmp_seq=2 ttl=64 time=0.047 ms
64 bytes from london01 (192.168.0.100): icmp_seq=3 ttl=64 time=0.042 ms
64 bytes from london01 (192.168.0.100): icmp_seq=4 ttl=64 time=0.041 ms
--- london01 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3002ms
rtt min/avg/max/mdev = 0.041/0.045/0.050/0.003 ms
[tideway@london01 ~]$