I'm no expert ...

BUT base-64 encoded  is plain text and might be sent in the body w/o
MIME headers. IIRC, LISTSERV does not block plain text attachments.
Depending upon your MUA, it might create a file.

Using a mimimum / appropriate SIZELIM= will help reduce  the likelihood
of virus encodings being transmitted.

The below error message may or may NOT be a function of your list's (not
LISTSERV(R)) distributions.  Email has been known to be spoofed and/or
false positives of a/v software.

Did you receive the email?  Is it in the archives for your to inspect
e.g., the headers?

/P

On 8/14/2010 4:23 PM, Ron Beatteay wrote:
> My list configuration is set to plain text
> only.  Wouldn't that block attachments or
> any extracurricular files?