On a linux machine, the “ifconfig –a” command will look something like this:

root@RS1 $ ifconfig –a

eth0 Link encap:Ethernet HWaddr 00:00:00:00:00:bb inet addr: 195.30.70.11 Bcast: 195.30.70.255 Mask:255.255.255.0

UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:96561817 errors:526 dropped:0 overruns:5 frame:0 TX

packets:97174301 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:100 Interrupt:10 Base address:0x4000

lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 UP LOOPBACK RUNNING MTU:3924 Metric:1 RX packets:3985923

errors:0 dropped:0 overruns:0 frame:0 TX packets:3985923 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0

To create an additional loopback interface with an IP alias, use the “ifconfig” command like this:

root@RS1 $ ifconfig lo:1 <VirtualServiceIPAddress> broadcast 195.30.70.200 netmask 255.255.255.255

root@RS1 $ ifconfig lo:1

lo:1 Link encap:Local Loopback inet addr:195.30.70.200 Mask:255.255.255.255 UP LOOPBACK RUNNING MTU:3924 Metric:1

Note: If the machine reboots, this configuration will no longer be available. To set this permanently, some Linux configuration files need to be edited. Steps on how to do this vary from distribution to distribution.

The next step is to disable invalid ARP replies. Add the following to the /etc/sysctl.conf file:

net.ipv4.conf.all.arp_ignore=1

net.ipv4.conf.eth0.arp_ignore=1

net.ipv4.conf.eth1.arp_ignore=1

net.ipv4.conf.all.arp_announce=2

net.ipv4.conf.eth0.arp_announce=2

net.ipv4.conf.eth1.arp_announce=2