> MAIL FROM:<[log in to unmask]> > 501 Syntax Error. Unexpected Token '_' This is an illegal RFC822 address. Underscores are not permitted in domain names. > The Listserv software seems to be objecting to the '_' in the gw_mail part of > the address. Correctly so. > I have spoken to our network administrator about this, but he says he cannot > change this easily. Besides, he says, this is a legal groupwise address. It may be "legal" to Groupwise, but it is not a legal RFC822 address. LISTSERV is conformant to the standards. SMTP is correct in rejecting it.