changing hostname with out fouling up network connection?

bezdomny · 07-21-2008, 07:36 AM

Any suggestions on changing the hostname without fouling up the network connection? All the posts I have google'd warn of messing up the network connection if the hostname is changed, but I'm still not clear on the whole solution. Please don't hesitate to ask if I can provide more information, especially about the network connection. Thanks!

pinniped · 07-21-2008, 08:07 AM

Unless you have a static global IP or other LAN users remotely access your computer by name rather than IP, feel free to change your hostname.

If you have a static global IP, write it down. Then change your domain name entries as appropriate and change your hostname. You will only be able to access the computer remotely via IP until the DNS changes have propagated.

nx5000 · 07-21-2008, 08:54 AM

I think X window and at least KDE might not like an online change. Kde uses a cache directory with the hostname inside. ~/.kde/cache-<HOSTNAME>
But you only asked about consequences on network connections and for this I see no problem (appart from DNS propagation as pinniped said)

bezdomny · 07-21-2008, 08:57 AM

Thank you very much, pinniped and nx5000. I sure don't want to mess up my X server-- had that happen two weeks ago and it was a real pain. Thanks for the warning. I will try to follow your suggestions and let you know how it works.

bezdomny · 07-21-2008, 09:00 PM

Here's what I did:

1. changed the content of /etc/hostname
2. altered the 127.0.0.1 entry of /etc/hosts
3. rebooted

And it worked like a charm.

didn't find ~/.kde/cache-<HOSTNAME> but it turned out OK as Xserver has started w/KDE w/no problem.

Thanks again for your help, pinniped and nx5000.

bezdomny · 07-21-2008, 09:15 PM

Almost forgot. Before rebooting, also ran

Code:

 #hostname <new_hostname>

Cheers!

pinniped · 07-22-2008, 06:14 AM

I don't think you needed the reboot; should have been good enough to 'restart' the appropriate services. Then again, if you don't know beforehand what services to restart a reboot is the quick and dirty way.

bezdomny · 07-22-2008, 09:59 AM

pinniped wrote:

Quote:

I don't think you needed the reboot; should have been good enough to 'restart' the appropriate services. Then again, if you don't know beforehand what services to restart a reboot is the quick and dirty way.

Quite right, I didn't know which processes to start and stop (I'm not that clever with Linux), so I rebooted.

Here are some entries from this morning's /var/log/boot I find interesting and would like the board's opinion about:

Code:

Tue Jul 22 04:32:04 2008: /dev/mapper/oldhostname-root: clean, 359383/9404416 files, 8092517/18795520 blocks
Tue Jul 22 04:32:06 2008:   Found volume group "oldhostname" using metadata type lvm2
Tue Jul 22 04:32:06 2008:   2 logical volume(s) in volume group "oldhostname" now active

and likewise from this morning's # dmesg:

Code:

# dmesg
Linux version 2.6.25.9 (root@oldhostname) (gcc version 4.3.1 (Debian 4.3.1-2) ) #1 SMP Fri Jul 4 19:52:20 PDT 2008
Kernel command line: root=/dev/mapper/oldhostname-root ro
Adding 2715640k swap on /dev/mapper/oldhostname-swap_1.  Priority:-1 extents:1 across:2715640k

Did I overlook some files to modify, or a command? Does it even matter? Will these incidences of oldhostname conflict somehow with newhostname and cause problems?

Thank you for your time and expertise!

farslayer · 07-22-2008, 03:13 PM

This is a nice guide for checking and setting the hostname for future reference. Run through this and make sure you didn't miss anything..

http://www.cpqlinux.com/hostname.html

bezdomny · 07-22-2008, 05:44 PM

Thank you very much, farslayer. I'll go through it. I'm especially interested because my router now identifies this machine by its I.P. address but not by its new hostname. I'm wondering if I missed a file or other step and this guideline you've provided probably will answer my curiosity. Thanks again.

bezdomny · 07-23-2008, 07:20 AM

The router now recognizes newhostname. Here's what I did:

in /etc/dhcp3/dhclient.conf, I uncommented and edited the line:

Code:

#send host-name "andare.fugue.com";

Now the router recognizes newhostname. I think this topic is solved and concluded. Thanks, everyone!