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 …
July, 2010
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15 July
Mail Server Causing High Server Load
Question: My CPU usage on my server is very high, and it seems to be originated from my mail server. What could be the problem? Answer: If your mail server is sucking up valuable CPU power, there are a couple of possibilities, none of which are pleasant. 1. You or …
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14 July
Extra Large Log Files
Question: One of my Linux system log files has suddenly become very large (several hundred megabytes). What should I do? Answer: The first thing to find out is what exactly is happening in the log files. To see the latest log activity for your web server error log, for example, …
June, 2010
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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 …
May, 2010
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17 May
When You Are Accused of Spamming…
Question: My web host has accused me of being a spammer and has suspended my account. How do I prove I am not a spammer? Answer: Usually, you will only be accused of spamming in one of three situations: (1) you actually are a spammer, (2) your account is hosted …
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10 May
Catchall Email Addresses
In the world of web hosting, email addresses can either be real or aliases. A real email address is connected to a mailbox on the mail server. That mailbox will hold any messages sent to the address in queue, awaiting the user to either download it or access it from …
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4 May
MailScanner: Anti-Virus and Anti-Spam Filter
As the name implies, MailScanner scans incoming mail sent to users on a server and flags them, and handles them according to the server administrators configurations. It is one of the most popular virus/spam filters It is written in Perl and links with other packages in order to accomplish its …
April, 2010
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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 …
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1 April
How do I enable SSL/TLS in Dovecot mail server?
Dovecot is a popular POP3/IMAP server for Unix-like operating systems. It is available through most distributions, including RHEL, CentOS, and Fedora. To enable secure mail transactions, you will need to edit your /etc/dovecot.conf file as root. Uncomment the following lines: # Disable SSL/TLS support? ssl_disable = no # PEM encoded …
March, 2010
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31 March
How to handle known spammers
When you are faced with relentless spamming, it is a good idea to use tools that go beyond simple filtering. One way to stop SPAM is to develop some type of proxy that stops known spammers before the messages reach the mail server. Another is to rely on DNS black …