/sbin/ifconfig
to get a listing of your current devices. See which device your server IP is using (Eg: eth0), then for your additional IP, you'll just add another number to it with a colon, eg: eth0:0cd /etc/sysconfig/network-scripts
nano ifcfg-eth0:0
DEVICE=eth0:0
BOOTPROTO=none
ONPARENT=yes
IPADDR=1.2.3.4
NETMASK=255.255.255.255
ONBOOT=yes
ARPCHECK=no
/etc/init.d/network restart
/etc/init.d/startips start
/sbin/ifconfig
/etc/network/interfaces
and at the bottom of the file (assuming you already have eth0listed there), add eth0:0:auto eth0:0
allow-hotplug eth0:0
iface eth0:0 inet static
address 1.2.3.4
netmask 255.255.255.0
ifup eth0:0
As mentioned, this has very limited testing, so be very sure that the setting you're adding are correct. It's possible the box can become inaccessible if an error is made at this point (which is why we can't do this for you)ifconfig em0 1.2.3.4 netmask 255.255.255.255 alias
which should load the IP into the em0 device. Once confirmed that this worked, edit:/etc/rc.conf
and below the line that starts with:ifconfig_em0=...
you'd add an alias line, that looks like this:ifconfig_em0_alias0="inet 1.2.3.4 netmask 255.255.255.255"
/etc/rc.d/netif restart && /etc/rc.d/routing restart
Error, some other host already uses address 1.2.3.4
then add this line to your ifcfg-eth0:0 file:ARPCHECK=no
Error: Connection activation failed: The connection is not for this device.
NM_CONTROLLED=no