Usually making changes to crypto maps means taking the crypto map off the interface first, otherwise you can lock yourself out of the router and stop all traffic going through it. With the change you want to make, you *should* be able to do it without affecting all your other tunnels, but I woiuld recommend two things:
- Make these changes after hours during a scheduled outage time just in case
- Make these changes from the inside network of the 7200, not from the outside where the crypto map is applied.
Let's say the 2600's current IP address is 1.1.1.1, and its new address with the new ISP will be 2.2.2.2. On the 7200 you'll have config commands similar to these:
> crypto isakmp key address 1.1.1.1 mask 255.255.255.255
> crypto map 10 ipsec-isakmp
> set peer 1.1.1.1
> match address
> set transform-set
You need to do the following in this exact order:
> crypto isakmp key address 2.2.2.2 mask 255.255.255.255
> crypto map 10 ipsec-isakmp
> set peer 2.2.2.2
> no set peer 1.1.1.1
After that you should be good to go. Just make sure that the is the same in the new command as in the old.
Also, the number 10 in the "crypto map" commands I've shown may or may not be 10, just use whatever number is being used for the current old IP address of 1.1.1.1 when you enter in the new commands.
