What does dnl mean in sendmail.mc

Enable selected domains to be routed to a destination of choice, in some cases where [] parenthesis is used over-ride DNS. The default behavior of sendmail is to deliver by MX despite entries in the mailertable — square parenthesis []are used to note where mailertable over-rides DNS.

The square brackets are to over-ride DNS MX record lookup, which sendmail does by default despite there being an entry in the mailertable which would only get attempted if the default MX lookup failed , hence the square brackets instruct sendmail to over-ride DNS MX record lookup. See my nightmare post on this. The following feature enables the sendmail restricted shell, otherwise known as smrsh, this provides a minimal shell for when sendmail is performing certain commands from the shell.

Masquerading is made up of a number of configuration directives. These directives control what parts of the header are re-written and for what domains the masquerading effects. This is normally limited to local domains only and is intended to over-ride the domain name for local mail destined outbound. The mailer section defines the local transports available, and the order in which the transports are used in the case of smtp and uucp where smtp has to come first.

At this point, it is well worth trying to discover the previous. Once discovered, this can be melded into your configuration. Now the configuration is complete, it is time to compile the. Ensure all files which sendmail. Ensure that all of the corresponding. It is important to follow up any restart whether successful or otherwise with a quick look in the messages or maillog file. If you find your new configuration does not work, check for and understand the differences between your new configuration and your previously known good configuration.

Are there things in the old config you stiill need like a MAILER procmail definition or some associated features and define fragments? Take Our Poll. Read the fscking manual? Have you SEEN the fscking manual? It is literally over pages! How can we not RTFM in our trade? You are commenting using your WordPress. You are commenting using your Google account.

You are commenting using your Twitter account. You are commenting using your Facebook account. Notify me of new comments via email. Notify me of new posts via email. This page is dedicated to showing you how to configure sendmail in a secure configuration. Why Sendmail? The reason why I choose sendmail is because of the following:- It is the oldest SMTP implementation It is the original SMTP implementation against which all others are measured It comes with almost every single UNIX distribution — while many Linuxes etc have chosen alternatives it has served only deviate Linux from what is otherwise a standard platform environment.

Right, now that you know about the macro file, we can start to configure sendmail. Here are a few quick tips to help you along.

There should be a file named sendmail. Editing this file is not only the proper way to configure Sendmail, but it is also much easier than trying to make your changes in sendmail.

To reduce the amount of spam you receive add the following line toward the bottom of your sendmail. This will check each incoming connection against one of the most reliable RBL s and if the IP address of the incoming connection is on that list it will bounce the message backing saying:. Some Linux distributions have Sendmail configured out of the box to accept E-mail from domains which do not have proper DNS information. To stop accepting E-mail from unresolvable domains just comment out this line in your sendmail.

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