I manage an ISP network with several C-Series appliances and as you might be aware, there are much infected hosts on ISP networks and therefore they send out spam.
This results in getting the outgoing IronPort IPs blacklisted.
I'm having some difficult blocking these spam/virus because if i turn antispam ON for outgoing mails, about 2/3 of outgoing mails are false positives. I don't know why IPAS classify these mails as spam.
I did put some rate-limiting,but this doesn't always help.
Does anyone of you have any recommendations on how i can minimize this problem?