Tag Archives: postfix

July, 2010

• 16 July

  How to Fix an Open Relay in Postfix

  

  As I have been reiterating all week, an open relay is a bad idea. If your mail server is left open, anyone can use your SMTP service to send mail, and spammers will use it. This can result in your server being blacklisted and extraneous use of system resources that …
• 15 July

  How Do Spammers Send Spam from My Server?

  

  When your server has become a haven for spammers, it is never a pleasant ordeal. Your server will probably be blacklisted, causing many of the emails you send to bounce back, and you may have serious connection problems due to the spammer using valuable system resources. There are a couple …

June, 2010

• 1 June

  PHP Mail Vs. SMTP Mailing Lists

  Whether your goal is marketing or simply communicating with your website’s online community, there comes a time when you need to send out a mass email. I am not suggesting you spam your customers or users. What I do suggest, however, is that you have some way of contacting people …

April, 2010

• 2 April

  How to change the Postfix port number

  By default, Postfix, Sendmail, and other SMTP mail servers rely on port 25 to send email. Normally, this is fine and works for most situations. Some Internet Service Providers, however, disagree. They see port 25 as a prime port for spammer exploitation, and many have started to block it. If …

February, 2010

• 26 February

  Limit the incoming email rate in Postfix

  Question: I have spammers sending multiple email messages to my mail server. How can can I limit the number of emails they can send in a given amount of time? Answer: This is a trick that many spammers and malicious hackers will use to flood your server with their nonsense. …

January, 2010

• 6 January

  Testing your mail server for an open relay

  Question: How do I make sure my mail server isn’t an open relay? Answer: First we should be clear on what an open relay is. According to spamhelp.org, an open relay is: “a mail server that does not verify that it is authorised to send mail from the email address …

December, 2009

• 30 December

  How to setup an SSL Dovecot mail server

  Question: How do I setup Dovecot to use IMAPS and POP3S with Postfix certificates? Answer: Dovecot is a free and open source IMAP and POP3 mail server. It is used for receiving incoming mail and works in conjunction with Postfix, which handles sending and delivery. Dovecot runs on all Linux …

November, 2009

• 27 November

  Tracking emails with Postfix

  Question: I am noticing some problems with my email server, Postfix. Is there a way to track emails? Answer: While you should definitely not use this for purpose of spying, it is sometimes necessary to track all emails on a server, even if you have multiple users on it. Sometimes …

October, 2009

• 29 October

  Email aliases file in Linux

  Question: How do I manually setup email aliases in Linux? Answer: Generally speaking, there is probably no reason for you to modify your aliases file manually. In some cases, however, a script will require you to edit the file, and it is important to know where it is and how …