We need to migrate our ASA from a T1 router internet connection to a DS3 router internet connection. Both routers and the ASA are connected to a switch. The ASA is currently configured and operating with a 184.108.40.206/25 IP range. The DS3 has a 220.127.116.11/27 and 18.104.22.168/27 IP range assigned to it. We don't use any special protocols.
I have read other posts which don't quite seem to address my need or contain insufficient detail for me to understand the steps and changes needed. We have web servers and internet users and cannot afford any significant interruption of service. We use static NAT for the servers and Interface PAT for the internet users.
The steps I believe I need are:
1. Setup two new outside IP ranges in the ASA.
2. Change the default gateway to one of the new ranges. (This should change over our internet users to the new router.)
3. Add new static NAT for the servers. (All servers have multiple internal IP addresses.)
4. Make DNS changes and wait for them to propogate.
5. Remove the old static NAT for the servers.
6. Remove the old IP range.
I assume this type of orderly migration is possible. I am unsure of the correct commands needed for steps 1, 2, and 6. I usually make changes in the ASDM but I am familiar with the CLI.
Thank you for your suggestions and guidance.