Loopback Interface Glitch?

[Nutz]

I was setting up a new router when I hit a snag. I placed the IP address 192.168.100.66/26 on the E0 interface. When I tried to put 192.168.100.126/26 on the Loopback 0 interface I got a network overlap error.

Router(config)#int e0
Router(config-if)#ip add 192.168.100.66 255.255.255.192
Router(config-if)#int loopback 0
Router(config-if)#ip add 192.168.100.126 255.255.255.192
192.168.100.64 overlaps with Ethernet0

Keep in mind that this is right after a fresh 'write erase' with no other configuration changes. What the heck was that all about? Hell, I even broke out the trusty old IP Calc and verified the IP scheme. Everything seems to have checked out. For the time being I've placed the loopback ip address at 192.168.100.190/26 and it seems to work fine.

 

[tjmaxz]

That's because they ARE on the same network.
Your network address is 192.168.100.64/26
and the range is .64-.127

You cannot put 2 addresses that are on the same network onto 2 different interfaces. I guess this is just a way to not let the router get confused. Or else the router would not know which interface to route to, given an address on that network.

 

[Nutz]

Ah, my bad. I was under the impression that logical interfaces would be exemt from that rule.