October 2001
Beginner
1024 pages
25h 8m
English
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Notes on Relaying
One of the most recent additions to Sendmail is protection against spam (unsolicited e-mail) through anti-relaying rules. These rules have been available for a long time, but only recently—as of Sendmail version 8.9—has the default configuration been to disallow relaying of messages from one server to another.
For a legitimate dial-up or remote user to use your SMTP server to send a message to another remote recipient, your server has to act as a relay, forwarding the message on to the recipient even if the message didn't originate from and wasn't addressed to anyone on its machine. Functionally, as illustrated in Figure 25.2, this is exactly how a spammer would send an unsolicited message to the same recipient through the same ...
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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.