I work with a client who needs to be able to run off 2 ISP's simultaneously for awhile until DNS fully converges. They are switching ISP's with new IP's but like I mentioned DNS updates take awhile and they cannot be down. On the new ISP side there will be a 2800 and ASA while on the old side a 2600 and Netscreen. If we switch the default gateway of servers to point at ASA we will end up with traffic coming in on the old ISP side and going out the new side, which won't work. Any suggestions how to do this temporarily?
I have this problem too.