While applying some eigrp network statements to a simulation, i noticed some curious behavors when utilizing different classes of networks. When apllying the network statement network 10.0.0.0 all of the expected interfaces began eigrp processes as anticipated. The same results were noted with the statement 172.16.0.0. The network statement network 192.168.0.0 however produced very different results. neither of the interfaces begginning with 192.168.x.x began eigrp proccesses. I surmise that the network statements must coinside with classful rules, thus the correct method for identifying the desired interface in the case of the classC address above would be to word the network statement to include the third octet as follows 192.168.1.x. I just want to ensure that my understanding of this bhavior is accurate. any help or clarifacation would be greatly appreciated.
In this particular case no, i understand that the addition of the wildcard would more accurately identify the desired interface(s) i leave out the wildcard often just to shorten statements aka. lazy lol. I just thought it was odd that EIGRP takes the class A and B address minus the wildcard and operates as anticipated. But in the case of a class C address operates differently.
it doesn't operate differently, when you specify no wildcard mask it will look at the interfaces addresses as classful and will compare with the classful address you configured in the network statement so as you already noted you must have a match on the first 3 octets here, for class B and A you need first 2 and first 1 octet match respectively.