I have an ASA5510 with a CSC module installed and it's configured to inspect all FTP, HTTP, POP3, and SMTP traffic going through the firewall. Yesterday at approx 3:30PM ET we had a problem with our email system, where we saw a lot of "Lost connection after RCPT from x.x.x.x" messages in our mail server. We were unable to send or receive any email to exterior organizations.
We did the standard checks -- check our MX records, check that we hadn't been blacklisted, etc. But the fix ended up being disabling the CSC module so nothing was being inspected.
Has anyone experienced something like this before?
Thanks in advance,