Routing the loopback's network address

[b.looney]

Can someone explain to me how a loopback address gets advertised to the rest of the network if it is on a different major network from both the serial and ethernet interfaces? I look at the routing table and it shows that this network is directly connected via the loopback 0 interface. EIGRP is the routing protocol of choice and there is a network x.x.x.x command for the loopback's network under our router AS number.

[rsissons]

The loopback interface is advertised in exactly the same way as a real interface provided you have a network statement for it.

By default, EIGRP will summerise on a major network boundary so, if you do not want this, you need to add the 'no auto-summary' command to the EIGRP configuration.