December 2002
Intermediate to advanced
1232 pages
56h 38m
English
Content preview from Sendmail, 3rd EditionBecome 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.
Name
HelpFile
Synopsis
The sendmail program implements the SMTP (and
ESMTP) HELP command by looking up help messages in a text file.
Beginning with V8.7 sendmail, help messages for
the -bt rule-testing mode are also looked up in
that file. The location and name of that text file are specified by
using the HelpFile option. If the name is the
C-language value NULL, or if sendmail cannot
open that file for reading, sendmail issues the
following message and continues:[34]
502 5.0.0 HELP not implemented
The help file is composed of lines of text, separated by tab characters into two fields per line. The leftmost field is an item for which help is offered. The rightmost field (the rest of the line) is the help text to be printed. A few lines in a typical help file might look like this:
help HELP [ <topic> ] help The HELP command gives help info. helo HELO <hostname> helo Introduce yourself. ehlo EHLO <hostname> ehlo Introduce yourself, and request extended SMTP mode. ehlo Possible replies include: ehlo SEND Send as mail [RFC821]
For an SMTP request of help vrfy,
sendmail might produce:
214-VRFY <recipient> 214- Verify an address. If you want to see what it aliases 214- to, use EXPN instead. 214 End of HELP info
The forms of the HelpFile option are as follows:
O HelpFile=file ← configuration file (V8.7 and later) -OHelpFile=file ← command line (V8.7 and later) define(`HELP_FILE',`file') ← mc configuration (V8.7 and later) OHfile ← configuration file (deprecated) -oHfile← command line (deprecated) ...
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.