I've been reading on this topic since it arose back about two weeks ago and wish to put in my devalued two cents for what it's worth. The 501 <@uga.cc.uga.edu:[log in to unmask]>... Unbalanced '<' is very likely a result of the mailer not recognizing the mixed (and valid) Internet fully qualified domain name in the routed address, but not the BITNET-style non-domain address. If so, following RFC 821 (Jonathan B. Postel's SIMPLE MAIL TRANSFER PROTOCOL document), the mailer is (properly) looking for a FQDN following the second "@" sign. Following the RFC, the first "@" sign followed by the ":" is the relay host and everything between ":" and ">" represent the destination user and host information arguments. If, for some reason, the machine reporting the 501 failure ("Syntax error in parameters or arguments" officially) is attempting to handle a VRFY or whatever on the FQDN of the destination, it isn't going to (and won't) find one since IUBVM.BITNET is not a FQDN. This could very well lead to a logically consistent unbalanced "<" since a recognized FQDN does not appear in the space following the second "@" and the trailing ">". I've seen this from a few places and it always appears that it is a result of a mixed FQDN-BITNET mapping in a To: or From: field. Short of malconfiguration on some machine, I don't understand why addresses of these types appear in To: or From: lines (I understand them fully in Return-path: lines, but not To: or From:, where gateway-types of addressing -- user%host1@host2 -- can be used; possibly someone can enlighten me on these variations). At least, that's what I've always attributed these sorts of 501 errors to and my subsequent reading leads to believe that's the central problem. Any comments on this theory? Regards, George %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% George D. Greenwade, Ph.D. Bitnet: BED_GDG@SHSU Department of Economics and Business Analysis THEnet: SHSU::BED_GDG College of Business Administration Voice: (409) 294-1266 P. O. Box 2118 FAX: (409) 294-3612 Sam Houston State University Internet: [log in to unmask] Huntsville, TX 77341 [log in to unmask] %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%