Problem solved!

 
Many thanks for the quick and correct reply.  I changed the Netware client cache settings (File Caching=Off, File Commit=On) on the XP host running Mercury32 and the problem cleared up immediately and has not reappeared in any of our traffic today.  It's peculiar that the error was most pronounced among our MSN correspondents, perhaps there's something special about the timing in the conversation with their servers.

 Your help with this is greatly appreciated.
 

David Morriss
 

We've just moved from running Mercury under Netware to Mercury32 on Windows and have quit using our ISP for forwarding outbound mail.  Most of our mail is working swimmingly, however, we're seeing a small percentage of message failures where the MAIL FROM: line has a SIZE=0 suffix and the response from the receiver's mail system is 501 Invalid arguments. 

Here's an example:

 12:38:51.906: --- Tue Apr 08 12:38:51 2008 ---
12:38:51.015: Connect to '65.54.244.104', timeout 60.
12:38:52.015: >> 220 bay0-mc3-f21.bay0.hotmail.com Sending unsolicited commercial or bulk e-mail to Microsoft's computer network is prohibited. Other restrictions are found at http://privacy.msn.com/Anti-spam/. Violations will result in use of equipment located in Califo
12:38:52.015: << EHLO mail.cherokeeporcelain.com<cr><lf>
12:38:53.296: >> 250-bay0-mc3-f21.bay0.hotmail.com (3.5.0.22) Hello [65.23.35.70]<cr><lf>
12:38:53.296: >> 250-SIZE 29696000<cr><lf>
12:38:53.296: >> 250-PIPELINING<cr><lf>
12:38:53.296: >> 250-8bitmime<cr><lf>
12:38:53.296: >> 250-BINARYMIME<cr><lf>
12:38:53.296: >> 250-CHUNKING<cr><lf>
12:38:53.296: >> 250-AUTH LOGIN<cr><lf>
12:38:53.312: >> 250-AUTH=LOGIN<cr><lf>
12:38:53.312: >> 250 OK<cr><lf>
12:38:53.312: << MAIL FROM:<Vicki@cherokeeporcelain.com> SIZE=0<cr><lf>
12:38:53.765: >> 501 Invalid arguments<cr><lf>
12:38:53.812: << QUIT<cr><lf>
12:38:53.062: >> 221 bay0-mc3-f21.bay0.hotmail.com Service closing transmission channel<cr><lf>
12:38:53.062: --- Connection closed normally at Tue Apr 08 12:38:53 2008. ---
12:38:53.078:

Most of these problems involve MSN/Hotmail addresses, though we're seeing it with some other addresses as well. 

Our configuration is a Netware network with ~10 users running PMail 4.41, SMTPMAIL directory on the Novell server (where it originally was with MERCNDS).  Mercury32 4.52 on a Windows XP system.

I've been digging through the forum looking for a hint as to what we can do to resolve the problem but I don't recognize anything that fits.  Any help with this is greatly appreciated. 

I've seen reports like this before but I'm not all that sure why it happens.  I'm guessing that something else has the message file open so when Mercury/32 tries to get the file size it gets a zero.  The first thing you should do is ensure nothing else is working on any of the files in the Mercury and/or temp directories.  This means if you are using anti-virus software make sure the Mercury directories are excluded from any autoprotection.  Might even look at write-behind caching as well.