Looking for (at) the right RFC's would have helped - and even interpreting the RFC correctly (regardless of which one I'm looking at) is something I need to work on -- my mistake. My firewall references "RFC 822 compliance" in the descriptor for a field where I can tweak the allowed hostname characters for any incoming connections - so I just jumped into 2822 to check it out and I got bogged down there. Thanks William and Ben for the clear responses. I will fix my system this morning.
randy. > -----Original Message----- > From: William Lefkovics [SMTP:[EMAIL PROTECTED]] > Sent: Monday, March 25, 2002 7:50 PM > To: MS-Exchange Admin Issues > Subject: RE: OT - RFC 2822 and the underscore from hell... > > Section 4.1.2 RFC2821: > > "To promote interoperability and consistent with long-standing guidance > about conservative use of the DNS in naming and applications (e.g., see > section 2.3.1 of the base DNS document, RFC1035std13 [22]), characters > outside the set of alphas, digits, and hyphen MUST NOT appear in domain > name > labels for SMTP clients or servers. In particular, the underscore > character > is not permitted. SMTP servers that receive a command in which invalid > character codes have been employed, and for which there are no other > reasons > for rejection, MUST reject that command with a 501 response." > > William > > > > > > -----Original Message----- > From: Toni, Randy [mailto:[EMAIL PROTECTED]] > Sent: Monday, March 25, 2002 2:49 PM > To: MS-Exchange Admin Issues > Subject: OT - RFC 2822 and the underscore from hell... > > > I'm trying to read through RFC 2822 to determine if an underscore is a > valid > part of a hostname for a mail server. We allow it on our SMTP proxy (any > host that connects to us with a "_" in the hostname is not a problem). > But > there is one server out there that is killing our outbound messages > because > a demo relay that I set up out in our DMZ has an underscore in the > hostname. > This hostname shows up in the header and they whack it (kind of rude but > maybe they're right to do so...) > > This is easy to fix but I'd like to know if I'm the one breaking the rules > here. Seems to me that the structure of a mail server hostname can > contain > an underscore (or a period, etc.) as part of the "atom" or "dot-atom" > component in the "local-part" of the "addr-spec" (which meshes with the > filbert-flange and the grapple-grommet). This stuff makes me dizzy > (dizzier?). I'm looking at > http://www.zvon.org/tmRFC/RFC2822/Output/chapter3.html#addr-spec Is there > anyone who can unscramble this doc for me and help with the sanity check? > The more I read it the more my brain resembles a dot-atom (but in spite of > that, BTW thanks to whoever it was who posted this site for RFC's) > > many thanks - as usual > randy. > > List Charter and FAQ at: > http://www.sunbelt-software.com/exchange_list_charter.htm > > List Charter and FAQ at: > http://www.sunbelt-software.com/exchange_list_charter.htm List Charter and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm
