I agree, We should provide better guidance on encoding of the UPN.
This should map with the format of UPN when provided in a certificate. The reference to the preferred name syntax is thus inherited from RFC 3280. This is how RFC 3280 restricts labels in the dNSName subject alt name. I will come back with a proposal on new text later today. Stefan Santesson Program Manager, Standards Liaison Windows Security -----Original Message----- From: Mark Andrews [mailto:[EMAIL PROTECTED] Sent: den 8 mars 2006 04:23 To: Eric A. Hall Cc: Kurt D. Zeilenga; ietf@ietf.org Subject: Re: draft-santesson-tls-ume Last Call comment > > On 3/7/2006 8:16 PM, Mark Andrews wrote: > > > * Hostnames that are 254 and 255 characters long cannot be > > expressed in the DNS. > > Actually hostnames are technically defined with a maximum of 63 characters > in total [RFC1123], and there have been some implementations of /etc/hosts > that could not even do that (hence the rule). RFC 1123 Host software MUST handle host names of up to 63 characters and SHOULD handle host names of up to 255 characters. 63 is not a maximum. It is a minumum that must be supported. > But even ignoring that rule (which you shouldn't, if the idea is to have a > meaningful data-type), there is also a maximum length limit inherent in > SMTP's commands which make the maximum practical mail-domain somewhat > smaller than the DNS limit. For example, SMTP only requires maximum > mailbox of 254 octets, but that includes localpart and @ separator. The > relationship between these different limits is undefined within SMTP > specs, but its there if you know about the inheritance. > > When it is all said and done, max practical application of mailbox address > is 63 chars for localpart, "@" separator, 63 chars for domain-part. > Anything beyond that runs afoul of one or more standards. > > </pedantry> > > -- > Eric A. Hall http://www.ehsco.com/ > Internet Core Protocols http://www.oreilly.com/catalog/coreprot/ > > _______________________________________________ > Ietf mailing list > Ietf@ietf.org > https://www1.ietf.org/mailman/listinfo/ietf -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: [EMAIL PROTECTED] _______________________________________________ Ietf mailing list Ietf@ietf.org https://www1.ietf.org/mailman/listinfo/ietf _______________________________________________ Ietf mailing list Ietf@ietf.org https://www1.ietf.org/mailman/listinfo/ietf
