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why does IGRP change the mask when using secondary ip address with a further subneted mask

why does IGRP change the mask when using secondary ip address with a further subneted mask w/o regard with split-horizon implications ?

I have:

Int s0

ip add 10.4.0.34 255.255.255.248

ip add 10.4.240.1 255.255.255.0 secondary

Int loop20

ip add 10.4.1.1 255.255.255.0

router Igrp

netw 10.4.0.0

________

The loopback gets advertised as 10.4.1.0/28 in the remote router directly connected to the serial0, completely the opposite of what you would expect.

1 REPLY
Anonymous
N/A

Re: why does IGRP change the mask when using secondary ip addres

Because IGRP does not support VLSM. You may consider usign EIGRP that supports VLSM.

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