I am seeing a few too many of "502 ESMTP command error" in the log reports each night (logwatch). Here are but a few examples:

"502 ESMTP command error",cmd: CELLPADDING=4><TR><TD colspan=2 align=center bgcolor=#C0C0FF><FONT FACE=arial><B><A : 8 Time(s)

"502 ESMTP command error",cmd: CONTENT-LENGTH: 4805: 16 Time(s)

"502 ESMTP command error",cmd: DATA: 697 Time(s)

"502 ESMTP command error",cmd: RCPT TO:<jo...@somedomain.com>: 20 Time(s)

They span from all sorts of html garbage (obvious spam), to actual commands that appear VALID (DATA: RCPT TO: HOST: SENDER:).

My question is... Should I be alarmed? Is esmtpd doing something bad that causes all these? Is it because esmtpd denies them relay, but they still spew forth data and esmtpd goes "WTF?!"...

Some counts: grep -c "502 ESMTP command error" maillog 2662 grep -c "513 Relaying denied" maillog 28219 grep -c "456 Address temporary unavailable" maillog 3879

These are the maxdaemon counts for a day: 35 active connections.: 6 Time(s) 36 active connections.: 5 Time(s) 37 active connections.: 4 Time(s) 38 active connections.: 5 Time(s) 39 active connections.: 4 Time(s) 40 maximum active connections.: 25 Time(s)