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Migrating from ASA5510(8.4.1) to 5525x (9.1x).. Should I be NAT worried?

I recently attempted to move from a ASA 5510 over to a spare 5520 running the same code (8.4.1) and ran into a problem with NAT to the Internet. I had set the same public IP address due to several vendors accepting only this certain address. So, when I migrated to the new 5520, NAT on this address did not work, meaning no traffic outbound would pass. However, if I change to another Public address no problems with traffic passing as expected. So my question is, I am migrating to a scratch-built 5525x using 9.1x code and will be using the same Public NAT address as on the 5510. Should I expect traffic to pass as expected or do I need to migrate to another address? Logic is telling me there should be no issues, but recent experience is making me jittery... Thanks for any comments Dave
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Hall of Fame Super Silver

Your recent experience may

Your recent experience may not have had anything to do with NAT per se even though that's how it manifested itself most obviously to you.

I suspect it may have had to do with your upstream gateway's arp cache. I have often seen when replacing hardware that we need to ask the ISP to flush their ARP cache so they can re-learn the new MAC address association to your pre-existing IP.

In any case, NAT should not be adversely affected when migrating from 8.4(1) to 9.1(x).

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Hall of Fame Super Silver

Your recent experience may

Your recent experience may not have had anything to do with NAT per se even though that's how it manifested itself most obviously to you.

I suspect it may have had to do with your upstream gateway's arp cache. I have often seen when replacing hardware that we need to ask the ISP to flush their ARP cache so they can re-learn the new MAC address association to your pre-existing IP.

In any case, NAT should not be adversely affected when migrating from 8.4(1) to 9.1(x).

As Marvin stated, your

As Marvin stated, your problem is more likely to be ARP related than NAT related. However depending on your nat configuration, i would advise you to look at the release notes for 8.4(2-5) as there are some changes regarding proxy-arp that might affect you.

New Member

Jan, thanks for the info. I

Jan, thanks for the info. I certainly will check it out. I know that 8.4 change the NAT game and this configuration was an upgrade from 8.2x. 

Regards,

Dave

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