Hi,
Since we are talking about the "outside" interface then theres a risk that it will have more configurations tied to it than perhaps some LAN or DMZ interface on the ASA.
To my knowledge there arent any easy or automated ways of migrating the configurations between interfaces and this kind of changes has always meant for me going through these steps
- Collect configurations related to the interface you are going to move to another physical/logical interface
- show run | inc is a good command to do this
- Removing the configurations from the interface about to be moved
- Reapplying some of the lost commands because of removing the "nameif"
- Reapplied NAT configurations
- Attaching the ACL back to the interface with "access-group in interface "
- Reapplied "route" configurations
- In your case you might also face the needs to reapply some VPN related configurations if the ASA is serving as a VPN device too
One more thought though...
You could considered doing the changes to "dmz" interface? Perhaps configuring ports 0/2 and 0/3 as FastEthernet Channel (FEC) between ASA and Core switch (if this setup is possible in your case)
I guess it wouldnt probably bring that much bandwith there to be enough.
You have to also take into account that the ASA5510 has its limitations and its throughtput (300Mbps total throughput, shown in the below linked documents) for traffic is way lower than for example the new replacing 5500-X series ASAs.
Heres a link to the documents related to performance
ASA 5500 Series
http://www.cisco.com/en/US/prod/collateral/vpndevc/ps6032/ps6094/ps6120/prod_brochure0900aecd80285492.pdf
ASA 5500-X Series
http://www.cisco.com/en/US/prod/collateral/vpndevc/ps6032/ps6094/ps6120/at_a_glance_c45-701635.pdf
Hopefully the above information has been helpfull
- Jouni
