amavis - the interface between mail server and spam / virus protection


Amavis is a server-side virus scanner written in the Perl programming language and used on Unix mail servers. If an unwanted email is detected, Amavis will automatically remove it from the market. Recently, the reliable program also blocked spam messages that would otherwise envelop the mail server. The useful tool can save a lot of time and the setting options leave plenty of room for an individual configuration of the mail server.

SpamAssassin reliably turns off viruses

An important part of Amavis is the SpamAssassin module. Regardless of the number of registered recipients, this spam blocker checks whether the message fits in the preset spam category or not. Thus, the mail server is not burdened too much with this task and all incoming messages are instead processed efficiently according to the wishes of each recipient centrally. In general, the combination of spam blocker and virus scanner works very resource-conserving. Amavis was written in Perl's programming language, with a particular focus on preventing buffer overflows while providing administrators with easy maintenance options. Amavis does not primarily see itself as its own virus scanner, but more as an interface that can be expanded with anti-virus programs such as SpamAssassin, ClamAV, Kaspersky LMS or AVG AV. Within this framework, threats to the mail server, as well as to the work computers, can be detected and prevented with minimal expenditure of time. Amavis is able to archive the messages or quarantine them. These can either be transferred to a mailbox or an SQL database. It is also possible with Amavis to create a DKIM signature. This identification protocol ensures that this is an authenticated mail. This prevents mail spoofing, which repeatedly creates serious security problems. Amavis supports a variety of different MTA settings. In general, the server admin has many setting options and can allocate the mail recipient into individual subgroups, which in turn work according to their own rules. For example, it is possible to receive spam messages with their own header notification tailored to the recipient.

Amavis convinces with good performance

Although Amavis was written in the programming language Perl, the software can still convince with a good performance. This is mainly due to the fact that large blocks of data are not traversed line by line, unnecessary copying of files has been prevented and the developers have shown a keen sense of optimization. In conjunction with the aforementioned anti-virus programs, one should nevertheless pay attention to which e-mails should be subjected to closer scrutiny. Just when the required identifier is present, exceptions can be defined that enable fast and timely editing. Above all, Amavis is committed to the defined RFC standards. The beginnings of the project partly go back to 1997. Incoming messages are forwarded to the Mail Transfer Agent via the well-known SMTP and LMTP protocols. If an unexpected event occurs during the mail transfer, a number of measures take effect immediately to secure the message. With this action package, Amavis prevents mail from being lost or messages made unreadable by a crash. Messages are not kept in memory, which prevents messages that are too large from causing a crash or serious server problems. An exception is only the transfer to the virus scanner SpamAssassin, but this is due to the operation of the scanner. This can be prevented by the Administrator sets a size limit on files so that messages above a certain size are not forwarded to the module, and instead must undergo a separate check. Certain senders can be entered in a blacklist or whitelist as with other mail server interfaces. This saves the mail server work and can sort out senders who have caused problems in the past or who do not need to be checked. Altogether Amavis compiles a convincing software package, which can easily be extended by further modules or virus scanners and proves to be a sensible interface.


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