I have a client that has 2 ATM circuits coming in to their building. They also have a Wireless Link from us to them that is active but not in use. They want to use us as a "security blanket" in case their ATM's go down, which has happened twice now. If i use Dial Backup for Serial Lines I would need to make an ACL to permit their IP space out of my Router correct? Does anyone have any other solutions or if they have done this before?