I'm not a Cisco ASA engineer but wanted to ask if it is possible to create a custom rule to filter a specific outbound email address, like [email protected], and assign it to pass thru a specific member of Ironport servers, like for instance Ironport server4762, every single time that email is used to send outbound email. Thanks much

  • I think you need a NextGen firewall that can do Deep Packet Inspection to peer into the application data.
    – Ron Maupin
    Commented Sep 25, 2017 at 14:17
  • SMTP routing requires an SMTP server. The point at which any email address is exchanged is deep into the conversation.
    – Ricky
    Commented Sep 26, 2017 at 4:54
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide and accept your own answer.
    – Ron Maupin
    Commented Feb 19, 2018 at 19:22

1 Answer 1


I don't believe the ASA will do that level of protocol filtering and rewriting for you. If I needed to accomplish that I would instead probably put another SMTP server in the path that mail needed to flow through before getting to the firewall and use rules in the SMTP server to redirect email as needed. You could then use a firewall to block all outgoing SMTP traffic except from the rule enforcing SMTP server.

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