Cisco 2600 and /23 classes subnet

[aalberty]

It has finally happened and we are out of useable IPs.

We are currently using the 192.168.0.0/24 range and I am trying to implement a 192.168.0.0/23 range.

All of our servers and printers are more than happy to use the 255.255.254.0 subnet, and even our PIX 515 works like a champ with the new range.

But for some reason, our Cisco 2600 router will not work after its IP address is changed. After "enable", "conf term", and "interface ethernet0/0", I enter "ip address 192.168.0.1 255.255.254.0", and "^Z".

As soon as the change is made, everyone on the network looses access to the router and the router cannot ping itself.

Is this because the 2600 will not allow a classless subnet, or am I missing something basic?

Thanks,

Adam

 

[MTandSAV]

try giving it a 'shut' first then change the ip and 'no shut'
i don't see any reason why it wouldn't work. I wouldn't change such thing either when 'everyone' is on the network, but thats something else.

CCNA, CCNP..partly

 

[Phobos1821]

Just a thought. Make sure you have this command enabled on the router.

ip subnet-zero

It lets you use all 1's, and all 0's subnets. May potentially be the cause of your issue.

 

[JOAMON]

Does your router have "ip classless" in the config??

 

[aalberty]

I wouldn't change such thing either when 'everyone' is on the network, but thats something else."

It's a little game I play with the head of payroll. I turn off her e-mail access and she threatens to take away my PTO! But seriously, by everyone I mean the computers on the network as the work is being done after hours and the users have gone home.

"Just a thought. Make sure you have this command enabled on the router.

ip subnet-zero"

This command is not currently in the config. Would I add this conf term area?

"Does your router have "ip classless" in the config??"

Yes ip classless is in the config.

Thanks for your help!

Adam