changing subnetmask on all servers

[CoolMike]

Hi

I have to change the subnet mask on all my cpanel servers in a few days. I'm wondering, is it enough if I change the file "/etc/sysconfig/network-scripts/ifcfg-eth0"? Or is there anything else needed? After I made the change there, do I need to restart a service?

I use Centos 3.5.

Thanks
Michael

 

[CoolMike]

I just realized in this file I have only the main IP adress, what about the second IP which I have configured on this servers? I did expect that there will be also a file ifcfg-eth0:1, but I did not find it.

Michael

 

[chirpy]

Run ifconfig to check how your IP addresses are bound. After making changes you need to down and up the interface. Remotely, this is best done with:

/etc/init.d/network restart

But do be aware that this can render the server inaccessible and may require a manual restart of the network from the console. If you have access to the console remotely, do that restart from there. If not, it might be better to simply reboot.

 

[CoolMike]

Hi Chirpy

ipconfig shows this:

eth0 Link encap:Ethernet HWaddr 00:C0:9F:3E:38:EF
inet addr:194.xxx.xxx.xxx Bcast:194.xxx.xxx.255 Mask:255.255.254.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:93779895 errors:0 dropped:0 overruns:0 frame:0
TX packets:143716683 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:3245413184 (3095.0 Mb) TX bytes:2427647214 (2315.1 Mb)
Base address:0xece0 Memory:fe2e0000-fe300000

eth0:1 Link encap:Ethernet HWaddr 00:C0:9F:3E:38:EF
inet addr:194.xxx.xxx.xxx Bcast:194.xxx.xxx.255 Mask:255.255.254.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
Base address:0xece0 Memory:fe2e0000-fe300000

But I have only a /etc/sysconfig/network-scripts/ifcfg-eth0 file and not a second one for eth0:1.

Where can I change the subnetmask for the second ip address?

Thanks
Michael

 

[chirpy]

They're setup by /etc/init.d/ipaliases and take the information from the file /etc/ips which contains, among other things, the network mask information.

 

[CoolMike]

Thanks a lot, this was exactly what I was looking for.

Michael