Postfix

Postfix provides Mime header check for all incoming messages. You can put restrictions on .exe / .bat / .vbs files and block all attachments. mime_header_checks directive allows you to define file, you will place a restriction for any file extensions that you do not want to have passing through your mail sever system. On most […]

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Librenix has a posted small and sweet article that explains basic steps to configure and install a mail server with antivirus / antispam in minutes. From the article: This article illustrates a situation where you need to set up your own mail server (be it your home mail server, or a small office one). It […]

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Postfix is free and powerful MTA. You can easily configure Postfix to block spam. You need to add following directives to /etc/postfix/main.cf file: => disable_vrfy_command = yes : Disable the SMTP VRFY command. This stops some techniques used to harvest email addresses. => smtpd_delay_reject = yes : It allows Postfix to log recipient address information […]

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Address rewriting allows changing outgoing email ID or domain name itself. This is good for hiding internal user names. For example: SMTP user: tom-01 EMAIL ID: tom@domain.com Server name: server01.hosting.com However when tom-01 send an email from shell prompt or using php it looks like it was send from tom-01@server01.hosting.com In some cases internal hosts […]

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Email filtering is an essential task. There are many methods like: => Bayesian spam filtering => SpamAssassin/DSPAM programs => Check open relay using RBL etc Now ORDB.org is shutting down its operation. ORDB is quite effective and I use this list against all of email servers. Spammers still use 3rd party servers and desktop computers […]

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PHP has mail() function to send an email to users. However this mail() will not work: => If sendmail (or compatible binary) is not installed => If Apache Web server / Lighttpd running in chrooted jail => And your smtp server needs an authentication before sending an email => Or you just need to send […]

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When you cannot monitor your server for service availability, it is better to take help of automated monitor and restart utility. Last 4 days I was away from my server as I was enjoying my vacation. During this time due to load my lighttpd webserver died but it was restarted automatically within 2 minutes. I had utility configured for monitoring services on a Linux system called monit. It offers all features you ever needed for system monitoring and perform error recovery for UNIX like system.

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