I'm not disagreeing with anything in this discussion. However I don't think we need to address this in the discussed document. The username in the defined domain hint is an account name and not necessarily a host name. Name restrictions in this case are thus governed by user name restrictions for the accessed system. Stefan Santesson Program Manager, Standards Liaison Windows Security > -----Original Message----- > From: Eric A. Hall [mailto:ehall@xxxxxxxxx] > Sent: den 7 mars 2006 21:06 > To: Mark Andrews > Cc: Kurt D. Zeilenga; ietf@xxxxxxxx > 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). > > 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@xxxxxxxx > https://www1.ietf.org/mailman/listinfo/ietf _______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf