This document describes the configuring steps required to configure ASA in transparent mode instead of routing mode in an existing network.
User is new to ASA's, he got a new asa 5510 (actually a refurb) and need to get it setup into existing network, He read it would be easier to put it in transparent mode than routing mode if you have an existing network and dont wanna redo the whole thing.
Current setup right now is,
internet > cisco leased router(with a set of external ip's from ATT) > juniper ns25( internal set of ip's mipped with the external) > internal network. So far user have put the asa in transparent mode and got the basics configured reading from some of the docs here and even some youtube vids, user read the docs on transparent mode for the ASA's
Question is on the BVI 1, it doesn't allow user to put the same ip range as his internal, it needed a different one like right now user have 192.168.1.1 on it.
User need to do this over console, what you can do to avoid getting disconnected is the next, when you have a laptop connected to the ASA and not through your network
Reload the ASA, it will come back up with the previous configuration if you saved it; log into the unit and instead of removing the IP address from the interface Management0/0 overwrite it and also remove the IP address from the BVI, folllow this example:
enableconfig tinterface BVI1no ip address 192.168.1.1 255.255.255.0