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New Member

Please help! Conversion to new 4506 and new subnet

Well, after thinking that I was in the clear on how I was going to make a major change to this company network on Saturday (two days from now), I discover that the Catalyst 4506 I'm planning on replacing a Catalyst 5500 with will not do what I was told (by Cisco) it would do. Basically, I cannot sub-interface.

So, I'm left to ponder other ways to resolve my problem. A little background...

The customer has a Cisco 3660 at the core of the network. It has two FastEthernet interfaces. One is configured with & and the other with & with class C subnets on all. (Here is where it gets spooky)

They run workstations and servers with those same subnet addresses (172.16.82.x, 172.16.100.x, 172.16.101.x and 172.16.1.x) but with a CLASS B SUBNET. (Yeah, I know - I didn't install it.)

So, anyway - we are removing all that stuff and putting in a nice simple 10.1.x.x network with a class B mask across the board. No secondary IP's or anything like that. However, I have a larger issue here.

All the remote sites (of which there are something like 80) all point to an IP address of (which is changing to and all these remote sites cannot be reconfigured. My earlier plan was to simply sub-interface a port on the Catalyst 4506 and plug in the address and happily move right along. However, the 4506 won't do that.


Can I NAT or Alias an IP on the 3660 for all the remote folks to be able to see the address they want to see ( even though the real address of the box is going to be

I hope so. Or is there SOME other way I can do this that I'm just not thinking of?

More detail? All remote sites are 172.16.x.x addresses also (yet another reason I'm moving them to a Class B subnetted Class A address). All local LAN will be 10.1.x.x.

Can anyone help me here or provide some insight? I'm waiting on Cisco tech support to call me back right now, I'm appealing to anyone for help at this point - as I need a miracle.

New Member

Re: Please help! Conversion to new 4506 and new subnet

I guess you can get the answer in the book.

<> Volume II

Jeff Doyle