We recently bought another company that had an old PIX box (PIX-501, SW version 6.3(4) ) on their network. As that box was old and barely (if at all) upgradeable, we decided to replace it with an ASA 5505. I copied the config as closely as I could, and we tried it. What we found was that it worked for the most part, but for some reason only a limited number of people could access the internet. Looking at the ASDM graphs, I'm seeing several hundred NAT translations in use at any given time, with a max of around 1,200, and there is nothing showing up in the log above informational level. The device is set up to translate all inside addresses to two outside addresses using PAT, but so was the old PIX box, so I wouldn't think that would be the issue. Where would be the next place to look, given that the logs are unhelpful (unless I just need to increase the logging level from warnings)?
I have this problem too.