Rejecting Valid User

[superstretched]

I've got a lot of incomming mail coming through 17 front-end gateways that use local hash files (domain and recipeints) to protect for open relay and valid users.

However, I'm starting to notice that mail destined to legitimate users is bouncing. They are in the recipients table, but I wonder if I've hit a limit. Currently, my recipients table has 71k records in it, is that too big? Should I go to mysql?

Thanks.