How do you release the address on an ASA-5505 configured to grab an address from the ISP's DHCP server? I can't find a command anywhere, or anything in ASDM.
under the outside vlan interface of the asa5505, you can assign a non-bia mac-address. assign it the same mac as your other router - if you know what that is. that way your ISP won't even realize you've been swapping gear on the line.