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Mail Avenger For Mac

3.4/5 11
GPL   

Highly-configurable, MTA-independent SMTP server daemon. #Spam filter  #Email checker  #Mail bomb protection  #Filter  #Check  #Protect  

Description

changelog

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Mail Avenger is a highly-configurable, MTA-independent SMTP server daemon. It lets users run messages through filters like ClamAV and SpamAssassin during SMTP transactions, so the server can reject mail before assuming responsibility for its delivery.

Other unique features include TCP SYN fingerprint and network route recording, verification of sender addresses through SMTP callbacks, SPF (sender policy framework) as a general policy language, qmail-style control over both SMTP-level behavior and local delivery of extension addresses, mail-bomb protection, integration with kernel firewalls, and more.

Mail Avenger runs on Mac OS X, FreeBSD, OpenBSD, Linux, and will likely run with little or no modification on other Unix-like operating systems.

Compared to traditional (.forward, .qmail, etc.) spam filtering, filtering during an SMTP transaction gives you more options. For instance, you can reject mail with an SMTP error code, causing a bounce only if the client is a legitimate MTA, not if it is a spambot.

Compared to traditional spam filtering, filtering during the SMTP transaction also gives you more information. Mail Avenger collects a wide array of information about SMTP connections from clients, including TCP SYN fingerprints (which often identify the client OS) and network route information.

Anomalies can be flagged when known senders exhibit radically different client behavior. Much of the information collected is also recorded in a new mail header, X-Avenger:, which can be fed to Bayesian content filters to improve accuracy.

Here are some key features of "Mail Avenger":

· Mail-bomb protection - prevents any single client from overloading your server. (See MaxConPerIP, MaxMsgsPerIP, MaxErrorsPerIP in the asmtpd.conf(5) man page.) · TCP filtering - can modify kernel firewall rules to block TCP SYN packets from overly aggressive clients. (See SMTPFilter in asmtpd.conf(5).) · Network-level traffic analysis - including collection of TCP SYN fingerprints, heuristic inference of client operating systems, and network route recording. (See CLIENT_SYNFP, CLIENT_SYNOS, CLIENT_NETHOPS, CLIENT_NETPATH, netpath in the avenger(1) man page, the synos(1) man page, and the pf.os(5) man page from OpenBSD.) · SMTP-level traffic analysis. (See CLIENT_COLONSPACE, CLIENT_HELO, CLIENT_PIPELINING, CLIENT_POST in avenger(1).) · SMTP callbacks - checks that mail senders can actually receive bounce messages. (See SENDER_BOUNCERES, MAIL_ERROR in avenger(1) man page, ClientTimeout, VrfyDelay, MaxRevClients in asmtpd.conf(5).) · Per-user and per-user-extension mail scripts - using Bourne shell syntax familiar to many Unix users. (See avenger(1).) · Per-user mail relay checks - allows users to permit relaying of their own email address from particular sources. (See avenger(1).) · Virtual domain mapping - maps all mail checks for a domain to a particular local user. (See DomainFile in asmtpd.conf(5).) · Alias to user mapping - allows filtering for mail aliases to be placed under the control of different users. (See AliasFile in asmtpd.conf(5).) · RBL support - query real-time black hole lists. (See RBL in asmtpd.conf(5), and rbl in avenger(1).) · SPF - sender policy framework blocks mail forgeries from domains that publish DNS SPF records. (See the "SPF CONFIGURATION PARAMETERS" section of the asmtpd.conf(5) man page.) · SPF language queries - scripts can dynamically formulate powerful queries using the SPF language. (See the spf function in avenger(1).) · Asynchronous DNS queries - for a, mx, ptr, txt records. Scripts can easily issue muitiple concurrent DNS as well as SPF, RBL, and traceroute queries. The setvars command then waits for them all to complete and assigns results to the appropriate variables. (See dns and setvars in avenger(1).) · "Bodytest" support - allows you to run filters like spamassassin and clamscan on the body of a mail message before replying to the final "." of the SMTP DATA command. (See the edinplace(1) man page and the bodytest description in the avenger(1) man page.) · avenger.local - a local delivery agent supporting qmail-style control over extension addresses. Users can create different extension addresses (e.g., [email protected], [email protected]) and route the mail differently. Also allows users to create and maintain their own mailing lists. (See the avenger.local(8) man page, and this example sendmail configuration.) · SMTP STARTTLS support - if OpenSSL is present when Mail Avenger is compiled. (See SSL and related directives in the asmtpd.conf(5) man page.) · Optional SASL support - with the Cyrus SASL package. (Use the --enable-sasl configure option, and see SASL in the asmtpd.conf(5) man page.)

What's new in Mail Avenger 0.8.4:

  • Switch to new resolver library interface, as previous way of reloading resolv.conf is no longer compatible with glibc.
  • Set IP_FREEBIND option if available.
  • Added systemd avenger.service file.
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Mail Avenger 0.8.4

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  runs on:
Mac OS X (-)
  file size:
890 KB
  filename:
avenger-0.8.4.tar.gz
  main category:
Internet Utilities
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