December 2003
Beginner
278 pages
10h 47m
English
Content preview from Postfix: The Definitive GuideBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Other Considerations
You can run multiple content filters, if necessary, by chaining them. If, for example, you have both an anti-virus and an anti-spam content filter, simply configure the first one to deliver to the next one rather than immediately back to Postfix. The Postfix configuration doesn’t have to change from what’s presented here. Only the final filter delivers the message back to Postfix.
Be aware of any email address rewriting that occurs before your filter receives a message. When the filter resubmits a message, if the rewritten address isn’t in one of the recipient maps, Postfix will reject it. You may have to turn off address rewriting in your normal SMTP server and configure it instead in your SMTP server that accepts messages back from your filter.
Some filters recommend that you configure them to accept mail in front of your normal MTA, and then they pass the messages on to your MTA after processing. You probably do not want to do this. Postfix is specifically designed to accept messages over an unfriendly network. A content filter is specifically designed to deal with processing the contents of messages and probably isn’t optimized for dealing with the load and potential hazards of accepting connections from the outside. Likewise some filters want to handle the final delivery of messages without re-injecting them into Postfix. Again, Postfix offers a lot of flexibility and security in dealing with the final disposition of messages that you might lose by delegating ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.