DUPFILTER(8) | Double Precision, Inc. | DUPFILTER(8) |
NAME¶
dupfilter - Sample Courier mail filterSYNOPSIS¶
filterctl
[[start] | [stop]] [dupfilter]
DESCRIPTION¶
This is an example global mail filter written in C. This is a threaded filter that tries to block junk E-mail by attempting to detect multiple copies of the same message, which are rejected. This filter is presented mostly for educational purposes. It´s method for detecting duplicate messages is rather simplistic, and, over time, ways of defeating it will certainly proliferate.BUGS¶
This is not a very smart mail filter. The hash function is very simple and is not expected to be very useful. Don´t even think of using dupfilter on a machine that either runs a mailing list, or contains mailboxes that subscribe to mailing lists. dupfilter likes to bounce mailing list traffic.FILES¶
This file contains a single numerical value
that sets the size of dupfilter´s circular FIFO queue.
/etc/courier/filters/dupfilter-duplevel
This file contains a single numerical value
that sets how many identical messages dupfilter will tolerate before
blocking them. When this many identical messages are seen, dupfilter
will start rejecting all messages with the same content.
/etc/courier/filters/dupfilter-mode
If this file exists and contains the word
"all", dupfilter will create its socket in
/var/lib/courier/allfilters, otherwise the socket will be created in
/var/lib/courier/filters, see courierfilter(8)[1] for more
information.
/etc/courier/filters/dupfilter-nthreads
This file contains a single numerical value
that sets the number of threads created (each thread is used to calculate a
message´s hash value). The default number of threads is 4.
SEE ALSO¶
AUTHOR¶
Sam VarshavchikAuthor
NOTES¶
[set
$man.base.url.for.relative.links]/courierfilter.html
04/04/2011 | Courier Mail Server |