Wild card on eigrp

[localbuilt]

Im a bit confused with the wild card when setting up the eigpr routing policy. Can someone help me understand what these means. I know Im suppose to ignore the first 3 octets..

network 192.168.51.100 0.0.0.3
network 192.168.63.0 0.0.0.127
network 192.168.63.0 0.0.0.255

 

[ADB100]

As with ACL's the wildcard mask is inverse.

Consider the following configuration:

interface FastEthernet0/1
 ip address 192.168.63.126 255.255.255.128
!
interface FastEthernet0/1
 ip address 192.168.63.254 255.255.255.128
!

By default if you wanted both these interfaces to run EIGRP and be included in the same EIGRP AS then you would configure:

router eigrp 10
 network 192.168.63.0

and this would work fine. However if you wanted one interface in one EIGRP AS and the other in a different AS then you would need to use the wildcard masks:

router eigrp 10
 network 192.168.63.0 0.0.0.127
!
router eigrp 20
 network 192.168.63.128 0.0.0.127
!

You could also go the other way and use a network statement with a supernet mask to cover multiple interfaces that share the same 1st part of the network address:

interface FastEthernet0/0
 ip address 192.168.1.254 255.255.255.0
!
interface FastEthernet0/1
 ip address 192.168.2.254 255.255.255.0
!
interface FastEthernet1/0
 ip address 192.168.3.254 255.255.255.0
!
router eigrp 10
 network 192.168.0.0 0.0.255.255
!

HTH

Andy

 

[brianinms]

Its merely an inverse of the actual mask.

http://www.mindflip.com/inet/tcpip/subnets.html

 

[Minue]

The matching is saying all addresses/interfaces in the below subnet can participate in the Eigrp routing process.

192.168.51.100 255.255.255.252
192.168.63.0 255.255.255.128
192.168.63.0 255.255.255.0


Regards

 

[burtsbees]

Take the mask and subtract it from 255.255.255.255...

255.255.255.255 minus 255.255.255.128 = 0.0.0.127

Burt