Using DCC with MUAs: Eudora 5.x for Windows

[In which I present a long overdue response to a request from Vernon to
assist in building a list of MUAs that can filter on DCC headers.]

----- Overwiew -----
Eudora 5.x for Windows includes in its filter arsenal the ability to match
based on regular expressions.  This feature works only in Sponsored (ads in
a little window) and Paid (send $) Modes; it does -not- work in Lite (no
ads, no $) Mode.  The feature allows a sufficiently motivated individual to
construct filters based on X-DCC headers.

Using the filter dialog, it goes something like this:
--------------------
--Match--
Incoming 
  [checkbox]
Header: X-DCC-<whatever>: 
  [will not be on the dropdown list, but can be typed in]
matches regexp
  (enter regexp in field next to "matches regexp")
ignore
  [ignore subsequent matching criterium]
  [optional: use and/or/unless and add another filter criterium]
--Action--
  [select up to 5 desired actions from the available list]
--------------------


----- Example -----
The following example uses an expression Vernon supplied as its basis:
>An example GNU egrep expression that matches X-DCC header lines
>for body counts >=50 is
>  ^X-DCC.* (Body|Fuz[1-4])=(many|[5-9][0-9]|[0-9]\{3,\})

Eudora doesn't support wildcards in the Header: field.  However it
certainly seems possible to construct a filter using the <Any header>
option in the Headers: field, coupled with a suitable regexp, to provide
equivalent functionality.  I'll defer that particular example to the regex
gurus;  below is an example that will match on a single header.

-------------------
--Match--
Header: X-DCC-MAPS-Metrics: 
matches regexp
  (Body|Fuz[1-4])=(many|[5-9][0-9]|[0-9]\{3,\})
ignore
--Action--
Transfer to
  Probable Junk
Skip Rest
-------------------

Windows Eudora stores its filters in a text file called filters.pce.  The
relevant portion of that file for the filter above looks like this (for my
particular mailbox/folder construct):

--------------------
rule X-DCC-MAPS-Metrics:(Body|Fuz[1-4])=(many|[5-9][0-9]|[0-9]\{3,\})
transfer NetAbuse.fol\PROBABLE.MBX
stop 
incoming
header X-DCC-MAPS-Metrics:
verb regex
value (Body|Fuz[1-4])=(many|[5-9][0-9]|[0-9]\{3,\})
conjunction ignore
header 
verb contains
value 
--------------------


----- Notes -----
1) Eudora uses its own regex interpreter, and I'm told by folks more expert
than myself that their implementation is just a tad buggy.  The manual
asserts that "Eudora uses the POSIX implementation."  
2) The filter dialog checks the regex for syntax and produces appropriate
error messages if it finds a boo-boo (which seems like a nice feature to
this regex newbie).
3) Eudora processes filters in the order they appear in its Filters dialog.
The Actions section includes  <Skip Rest> which should be liberally applied.
4) There is a version of Eudora 5.x for Macs.


----- Recommended reading -----
- Background information on Eudora filters, including tips on construction,
filter order, and using filters to stop spam -- but NO information on using
regex:
  <http://wso.williams.edu:8000/~eudora/frame-faqs.html#filters>
- Eudora Manual/Help file, especially:
    Detailed Filters with the Filters Window
    Regular Expressions (Sponsored and Paid modes only)
  Windows manual (4.2MB)
  <http://www.eudora.com/download/eudora/windows/5.1/full_elec/Manual51.pdf>
  Mac manual (3.3MB)

<http://www.eudora.com/download/eudora/mac/5.1/final/Eudora5.1_Manual.sit.hqx>
- Eudora recommends the following site for regex information:
  <www.robelle.com/library/smugbook/regexpr.html>


----- More information -----
- Eudora FAQs and Links: <http://wso.williams.edu:8000/~eudora/>
- newsgroup: comp.mail.eudora.ms-windows
- I have used Eudora filters for many years and find them to be highly
flexible, customizable, and reliable.  I'd be happy to provide such help as
I can.


Regards,
-wdb