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.
Log with syslog
Logging is the process of issuing one-line messages or warnings that will be either displayed to a human, archived to a file, or both. The mechanism that sendmail uses to produce these logging lines is called syslog(3). The sendmail program is concerned only with issuing its messages and warnings. Once they are issued, the syslog facility takes over and disposes of them in a manner described in the file /etc/syslog.conf. Statements in this file determine whether a logged line is written to a device (such as /dev/console), appended to a file, forwarded to another host, or displayed on a logged-in user’s screen.
In the following discussion of syslog and syslog.conf, we will describe the BSD 4.4 version. Some versions of Unix, such as Ultrix, use the 4.2 version of syslog, but because syslog is public domain, we recommend you upgrade and will not cover that old version here.
syslog(3)
The
syslog(3) facility uses two items of information
to determine how to handle messages: facility
and level. The facility is the category of
program issuing a message. The syslog facility
can handle many categories, but only one, mail, is
used by sendmail. The level is the degree of
severity of the warnings. The sendmail program
issues messages with syslog(3) at various levels
depending on how serious the message or warning is.
When sendmail first starts to run, it opens its connection to the syslog facility with the following C-language line:
openlog("sendmail", LOG_PID, LOG_MAIL); ...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.