Netmask question ?

Just noticed my isp have changed netmask to 255.255.240.0
how or where do i correct this ?

Thanks in advance for your reply :smiley:

You can view your netmask using ifconfig in a root shell.

To change it, I beleive you do cd /etc/sysconfig/networking/devices and then nano ifcfg-eth0

Obviously change to your favorite text editor, and the right ethernet device if applicable.

Inside the file you’ll find stuff like this:

BOOTPROTO=none
HWADDR=00:0C:6E:1B:05:46
DEVICE=eth0
MTU=""
NETMASK=255.255.255.0
BROADCAST=192.168.2.255
IPADDR=192.168.2.2
NETWORK=192.168.2.0
ONBOOT=yes

Just change the NETMASK line to what you need, and then do /etc/init.d/network restart

Note though, that this is just how I would do it - It should work, but if it goes wrong and leaves your box un-connectable, don’t blame me :wink:

Hope this helps :slight_smile:

On a RedHat/Centos box the file is
/etc/sysconfig/network-scripts/ifcfg-eth0

[quote=pascal;9603]On a RedHat/Centos box the file is
/etc/sysconfig/network-scripts/ifcfg-eth0[/quote]

Thats correct, thank you

i also have additional ip where do i go to change the netmask on those.

thanks again for your help

/etc/sysconfig/network-scripts/ifcfg-eth0:1
/etc/sysconfig/network-scripts/ifcfg-eth0:2

etc etc :slight_smile:

thats where i thought they where but i dont have those in that dir

/etc/sysconfig/network-scripts/ifcfg-eth0:1
/etc/sysconfig/network-scripts/ifcfg-eth0:2
/etc/sysconfig/network-scripts/ifcfg-eth0:3

/etc/sysconfig/network-scripts/ifcfg-eth0 lists every thing as it should

ifconfig shows all ips ect

/etc/sysconfig/network-scripts/ifcfg-eth0-range0
/etc/sysconfig/network-scripts/ifcfg-eth0-range1
etc

no not there either, thanks again

going to post support ticket