JSpamFilter is a Java-based TCP proxy intended for use with SMTP mail servers.
JSpamFilter is inserted into the mail flow and performs both source and content checks on incoming email before that mail gets to your mail server.
In general, you'll set your existing mail server to listen on port 26, then set up JSpamFilter to run on port 25 (this is the default configuration).
Click the links below for illustrations of some common configurations:
JSpamFilter provides a full suite of content and source analysis tools to examine and analyze incoming mail and a variety of treatment and identification options to subsequently handle and route messages.
The System Administrator managing JSpamFilter selects whether to use the DNSBL-checking features, along with which DNSBLs to use and how to weight the DNSBL-lookup results.
When someone tries to connect to your mail server, JSpamFilter compares
their IP address against one or more DNSBL(s) configured by doing a DNS lookup with the reversed IP address plus ".bl.spamcop.net"
(name varies by DNSBL). If each IP address lookup fails (the source is not
a known spammer), then a connection is established from JSpamFilter to port
26, and the connection is allowed to proceed.
Depending on the settings made by the System Administrator,
if the remote sender is on one of the lists, their connection is refused or
tagged to identify it as likely being spam email. The selection which DNSBLs to use and how to weight their results
is customizable. Blacklisted addresses receive
a reply similar to the
550 mail Service not available due to [servicename] blackhole
Content analysis can be performed using direct keyword and keyphrase searches along with advanced probabalistic and rule-based analyses to combine and weight analysis results.
Content checks also include full header analysis, along with script and mark-up element analyses.
Using probabalistic and statistical checks, a score is constructed based on the content of the message.
JSpamFilter provides a variety of treatment and identification options to subsequently handle and route messages.
Based on settings made by the System Administrator, email messages are handled in several ways.
- Forwarded to the end-user untouched
- "Tagged" as likely being spam, but forwarded to be handled by the end-user's email client. Tagged mail can then be routed to a particular folder in the end-user's email client (e.g., Microsoft Outlook, Lotus Notes, Novell Groupwise Client, etc.) for later examination.
- "Blocked" prior to arriving at your mail server. Blocked mail can be either refused at the gateway or routed to a global "garbage" email account.
The mail handling options are determined by the thresholds set by the System Administrator, and the choices in analysis options.
By using a global garbage email account, the possibility of "false positives" (i.e., messages accidentally rejected) can be eliminated.
All of the parameters controlling JSpamFilter's behavior can be adjusted by the System Administrator to best suit your needs.
JSpamFilter helps you prevent abuse of your mail server.