Is there a way to filter posts based on the content of the MIME header? I've just discovered that my list allows something through which triggers a flood of rejections because of security concerns. It was an attachment of the .url type. The problem is that we need to allow attachments with the MIME Content-Type of "application/octet-stream"; we exchange files that are often conveyed that way in the course of our work. However, if such a file carries a .url extension, it is (wisely) considered unsafe by many email servers, producing a flood of rejections. (I've gotten 15 so far, some for multiple subscribers--and that's only the ones that slipped past the error summary!) I was hoping, therefore, to filter on the file extension, and just refuse to allow the string ".url" to be sent at all. However, I can't seem to find a way to catch it in the content filters. LISTSERV appears to regard material in MIME headers as neither a header entry (so I can't write a filter starting with "Content-Type:") or message text (so I can't just filter on ".url" itself). Is there a way to do this? or is that part of a message just plain immune to examination by LISTSERV? Hal Keen