Effect of assigning wrong IP to router interface

[ayo_adesanya]

What are the possible effects of assigning an invalid address like 172.22.0.0 255.255.255.252 to a router interface. The 1841 router accepted the address. Thanks.

[paolo bevilacqua · Accepted solution]

And why that should be an invalid address in your opinion ?

[ayo_adesanya]

172.22.0.9 255.255.255.252 should only support 2 addresses i.e: 172.22.0.1 - 172.22.0.2.

[paolo bevilacqua]

ayo_adesanya wrote:
172.22.0.9 255.255.255.252 should only support 2 addresses i.e: 172.22.0.1 - 172.22.0.2.

I recommend that you go back at studying addresses and netmasks ...

[ayo_adesanya]

I actually meant to write 172.22.0.0 with mask 255.255.255.252. Thanks

[Dan-Ciprian Cicioiu]

Hello ,

172.22.0.9 255.255.255.252 is a valid address also 172.22.0.10

the network address is 172.22.0.8 and the broadcast is 172.22.0.11

Dan

[ayo_adesanya]

My mistake. I meant 172.22.0.0 255.255.255.252.

[jgraafmans]

There is nothing wrong with this IP address. With this mask the IP address is part of a subnet of 4 addresses. 172.22.0.8 - 172.22.0.11 where 172.22.0.8 is the network address and 172.22.0.11 is the broadcast address and are thus not useable. If you connect a PC and give it IP address 172.22.0.10 you should be able to ping 172.22.0.9 successfully.

[ayo_adesanya]

My mistake. I meant 172.22.0.0 which should support 172.22.0.1 - 172.22.0.2 ordinarily. But 172.22.0.9 was assigned to a router interface. It accepted the address and appears to be okay but since 172.22.0.0.255.255.255.252 should be limited to 172.22.0.1 - 172.22.0.2, could assigning 172.22.0.9 have an effect? I think it should but I've not noticed any direct effect. Also I have ocassional performance issues with the router and I'm wondering if this could be the cause.

Thanks for your time.

[ayo_adesanya]

My mistake. I meant 172.22.0.0 which should support 172.22.0.1 - 172.22.0.2 ordinarily. But 172.22.0.9 was assigned to a router interface. It accepted the address and appears to be okay but since 172.22.0.0.255.255.255.252 should be limited to 172.22.0.1 - 172.22.0.2, could assigning 172.22.0.9 have an effect? I think it should but I've not noticed any direct effect. Also I have ocassional performance issues with the router and I'm wondering if this could be the cause.

Thanks for your time.

[paolo bevilacqua]

That is made to support /31 masks, and save addresses. It's ok to do that if you want.

[cadet alain]

Hi,

depends, but e.g if you are using routing protocols like OSPF or EIGRP then you could lose adjacency.

what is your topology?

Regards.

alain.

[cadet alain]

Could you be a little bit clearer please

Thanks.

Regards.

Alain.