I think I know what happens. There was a bug in the RFC822 parser of LISTSERV. It was documented as returning the REPLYTO information in what I called 'address format', ie: localpart <blank> domainpart <blank> full name However for some reason I had called the wrong routine in the code which caused the parser to return the contents of the field 'as is'. In 1.5k I corrected this and the parser now works as documented and as intended. The mail processing routine also expected the parser to return addresses in the format above. Thus we were getting Reply-To fields of the form: FRECP11 <Eric@Thomas> Now this problem is fixed. But it seems to appear that there is still one place in the code which I overlooked when converting from the 'internal' parser in LSVXMAIL to the full RFC822 parser (LSV822IN), and this place expects the stuff in the 'old' format. I don't know where it is as I don't have room to keep the code at UKACRL (I could only get 5 cylinders of disk space, and only so after complaining). Eric