I always had this question. Is there anybody can answer?
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Under DHCP, the hostname is set to localhost during Linux installation. This is true for /etc/hosts and /etc/sysconfig/network under Redhat installation. The IP address will set by DHCP server that could be either DHCP server or router. If I would like to set a name for the computer, say "MyCom", then how can I do that? The /etc/hosts file is requires IP address to set but it comes from DHCP server. The network file can be modified to reflect the new hostname for the computer, but it genereate an error during boot process. The error asks to change /etc/hosts to add the name, but the IP address can't be set under DHCP.

Any clue for this??

as root:

# hostname MyComp (or whatever you wanted)

Should do the trick.

Be aware: a FEW (and I do mean very few) dhcp servers only assign addresses to hostnames that it recognizes. If you can't get an ip after you change your hostname, it probably shouldn't be changed. Though, I don't see this happening in your case as you get an ip address with the hostname localhost, which, if I were running a dhcp server that authenticated by hostname, would be one of the first blacklisted.

You also might need to log out and log back in to notice the effect in your bash prompt and such.

Hello, bdogg

I did as what you suggested. After the change, however, when I login to the computer, it gets an error!! That is what I described in my previous message.
The error is :
"Could not look up internet address for MYHOSTNAME. This could prevent GNOME from operating correctly. It may be possible to correct the problem by adding MYHOSTNAME to the file /etc/hosts".

Here I have a problem! Because with DHCP I can't assign IP address to the hostname that is required in /etc/hosts.

Any help is appreciated!

I am having a little trouble understanding your situation. It's good to inlude exact error messages, thanks for that.

Why can't it? Is it because you have configured your DHCP server (or your ISP has) so that it will block connections from that host?

Why is the hostname you are seeking "required" in /etc/hosts?


Step 1:
Your /etc/hosts file should read like this

127.0.0.1 localhost.localdomain localhost (HOSTNAME U WANT)

And then any other IPv6 or IPv4 hosts you want to note.

Step 2:
Remember the last half of my first post? When a DHCP server tells you that it can't assign an ip to the hostname you have chosen, it's something with the DHCP server that needs fixing.

AS WELL, GNOME looking up your hostname is different from a DHCP server giving you an IP.

Step 3:
You could also check /etc/hostname and put your hostname there.

Then you could go to /etc/hosts and add a line like so

127.0.0.1 (HOSTNAME U WANT)

That would fall right under your first line that reads ... localhost.localdomain ... etc

Hello, Bdogg

First of all, thank you for your help on this. No matter what I get at the end of this discussion, I am sure I will learn a lot on Linux. Thank you for it.
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>>Why can't it? Is it because you have configured your DHCP server (or your ISP has) so that it will block connections from that host?

Ans: The host I am talking about is my machine. I have a home network with DSL and a router. As far as my knowledge goes, the router governs the IP address, so that it is not ncessary to set the IP address in /etc/hosts file. If I set it up, DOES DHCP OVERWRITES IT? I found that this computer always gets 192.168.2.7 ( I have 4 computers on the network ), should I change the /etc/hosts as follows?

127.0.0.1 localhost.localdomain localhost (this is for loopback)
192.168.2.8 MYHOST

or just
127.0.0.1 localhost.localdomain MYHOST

>>Why is the hostname you are seeking "required" in /etc/hosts?

Ans: Because GNOME yells at the login process as I mentioned in the message. If there is no error, then I would just leave this file without any change.

if your computer always gets 192.168.2.7 then do it like this

127.0.0.1 localhost.localdomain localhost MYHOST
192.168.2.7 MYHOST

Try putting those two lines in your /etc/hosts file.

There are many files regarding hostname setup in Linux.

/etc/hosts
/etc/sysconfig/network
/etc/sysconfig/networking/devices/ifcfg-eth0
/etc/sysconfig/networking/profile/... (4 files are there)
/etc/sysconfig/network-scripts/ifcfg-eth0

Do you know each one and what use for??

I will change hosts file with hard number but that what I was confused with DHCP becuase it supposed to get the IP from the server...

Thanks..