HowtoForge - Linux Howtos and Tutorials - Postfix

Installing ehcp (Easy Hosting Control Panel) On Any Debian Or Apt-Get Based Distro, Including Ubuntu

Wed, 24 Oct 2007 12:50:34 +0200

Installing ehcp (Easy Hosting Control Panel) On Any Debian Or Apt-Get Based Distro, Including Ubuntu

In this tutorial I will show you howto install ehcp on any debian based distro, or any distro that has apt-get support. ehcp stands for Easy Hosting Control Panel. It may be used by anyone wanting to host multiple domains in his dedicated/vps server. It is a hosting control panel under development.

Set Up Postfix For Relaying Emails Through Another Mailserver

Wed, 24 Jan 2007 17:25:25 +0100

Set Up Postfix For Relaying Emails Through Another Mailserver

This short guide shows how you can set up Postfix to relay emails through another mailserver. This can be useful if you run a Postfix mailserver in your local network and have a dynamic IP address because most dynamic IP addresses are blacklisted today. By relaying your emails through another mailserver that is hosted on a static IP address in a data center (e.g. your ISP's mailserver) you can prevent your emails from being categorized as spam.

Enhance Your Mail Server With ASSP (Anti-Spam SMTP Proxy)

Tue, 07 Nov 2006 22:38:19 +0100

Enhance Your Mail Server With ASSP (Anti-Spam SMTP Proxy)

ASSP stands for Anti-Spam SMTP Proxy. The ASSP server project is an Open Source platform-independent transparent SMTP proxy server that leverages numerous methodologies and technologies to both rigidly and adaptively identify spam. In short ASSP is the most kickass solution that is both free and works great. It reduced spam to an absurd minimum for me.

One of the users on the system has a CatchAll-email address. He receives all emails, even those for users of another site...

Mon, 07 Aug 2006 17:47:30 +0200

One of the users on the system has a CatchAll-email address. He receives all emails, even those intended for users of another site on the same server. The MTA on the server is postfix.

Please check if the domain of the users that receives all emails is the same as the domain $mydomain in /etc/postfix/main.cf. If this is the case, change $mydomain and run

postfix reload

on the shell.

You should never enter a domain that is used for a virtual site on the server as $mydomain in /etc/postfix/main.cf!

I cannot send and/or receive emails.

Mon, 07 Aug 2006 17:43:37 +0200

Please check if Sendmail/Postfix and your POP3 daemon are running by executing

netstat -tap

You will get a list of all services listening on your server.

If they are running re-configure your firewall (iptables or ipchains) so that the ports 25 (Sendmail/Postfix) and 110 (POP3) are not blocked. If this does not help please check that Sendmail/Postfix is really running on port 25 and your POP3 daemon on port 110.

(Hint for standard RedHat installations: If you have webmin installed and are running Sendmail, go to Webmin->Servers->Sendmail->Sendmail Options. Under SMTP Port Options you often find the following entry:

How do I configure Postfix to use SMTP-Auth?

Mon, 07 Aug 2006 17:38:21 +0200

Some useful links:

http://www.thecabal.org/~devin/postfix/smtp-auth.txt
http://www.mandrakesecure.net/en/docs/postfix-sasl.php
http://postfix.state-of-mind.de/patrick.koetter/smtpauth/index.html
http://www.howtoforge.com/perfect_setup_debian_sarge
http://www.howtoforge.com/howto_postfix_smtp_auth_tls_howto

On sending emails, I get the following error message: "Relaying denied".

Mon, 07 Aug 2006 17:35:06 +0200

There are two solutions for this problem:

1) You configure your MTA to allow authentication via SMTP (SMTP-Auth). Your users then have to change settings in their email clients (e.g. Outlook), i.e., they have to activate Server requires authentication.

2) You install "POP-before-SMTP" or poprelayd on your server. Your users then have to fetch emails first before they are allowed to send emails for a restricted period of time (mostly 30 min.).

How can I find out which Postfix version I'm running?

Mon, 07 Aug 2006 17:34:44 +0200

Just run

postconf -d | grep mail_version

to find out your Postfix version.