Setting the Linux Host Name

Checking your Linux host name
First, see if your host name is set correclty using the following commands:
uname -n
hostname -a
hostname -s
hostname -d
hostname -f
hostname

If the above commands return correctly with no errors then all may be well; however, you may want to read on to verify that all settings are correct.



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Configuring /etc/hosts
If your IP address is assigned to you by a DHCP server, then /etc/hosts is configured as follows:
127.0.0.1 mybox.mydomain.com localhost.localdomain localhost mybox

If you have a static IP address, then /etc/hosts is configured as follows:
127.0.0.1 localhost.localdomain localhost
192.168.0.10 mybox.mydomain.com mybox


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Setting the Host Name using "hostname"
After updating the /etc/hosts file correctly, the "hostname" command should be run as follows to set your hostname:


hostname mybox.mydomain.com

--------------------------------------------------------------------------------Checking /etc/HOSTNAME (if present)

You may or may not have the file /etc/HOSTNAME:

mybox.mydomain.com


--------------------------------------------------------------------------------Checking /etc/sysconfig/network
If you have a static IP address, then /etc/sysconfig/network is configured as follows:
NETWORKING=yes
HOSTNAME="mybox.mydomain.com"
...


If your IP address is assigned to you by a DHCP server, and you wish to update the local DNS server through Dynamic DNS, then /etc/sysconfig/network is configured as follows:
NETWORKING=yes
HOSTNAME="mybox.mydomain.com"
DHCP_HOSTNAME="mybox.mydomain.com"
...


--------------------------------------------------------------------------------Checking /proc/sys/kernel/hostname

This is checked with the following command:
cat /proc/sys/kernel/hostname


If you need to set this file, you can either reboot or set it now with the following command:
echo mybox.mydomain.com > /proc/sys/kernel/hostname


--------------------------------------------------------------------------------Dynamic DNS - Updating the local DNS server with your host name and DHCP IP
If you receive your IP address from a DHCP server, you may update the local DNS server by adding the following line to /etc/sysconfig/network for Red Hat:
DHCP_HOSTNAME="mybox.mydomain.com"