On 7/8/2013 5:29 PM, Carl S. Gutekunst wrote:
FWIW
The "compose" dialogs on Microsoft Outlook 2010, Yahoo! Mail,
Live.com, and Gmail do not allow dotless domains. Yahoo and Live.com
reject the address as malformed; Outlook tries to look it up in the
local address book; Gmail gives an error on send.
Thunderbird 2.0 to my employer's Exchange server (over SMTP) worked
fine -- and then the message got rejected by the corporate firewall as
"invalid domain."
<csg>
The only real place I have seen dotless domains is with dealing with
NETBIOS computer names and the EHLO/HELO field.
Outlook will use the local computer NETBIOS name IFF a FQDN is not found
in DNS for the EHLO/HELO field. This all goes back to ARP and the
mapping with WINS. Outlook-based end users with NATs do not have
problems because SMTP, although technically required to be a valid
EHLO/HELO domain, historically, the EHLO/HELO can be a misconfiguration
hence when its a DOTLESS field entry no validation is possible.
OTOH, Tbird will use a domain IP literal and the IP can be wrong when
the private IP is used. This is a strong rule that can be used to
validate the connected IP with the machine IP, but TBIRD and others
behind a NAT local LAN need to be also configured to use the NAT IP or
the public FQDN domain, if any. The only place I seen a problem here
is with the SUBMIT protocol which requires a valid EHLO field. It
needs to be relax. In our port 587 connectivity implementation the EHLO
field validation is skipped because ESMTP AUTH is required anyway for
SUBMIT.
Part of the problem is what SOCKET API is used. Under Windows, if you
use the Windows SOCKET API, you can get the NETBIOS name when a IP
lookup is made. We had to change and force across the board DNS
record API lookup usage and avoid the Windows Socket API commands as
much as possible.
Dotless Domains are only valid within a LAN or internal WAN, but not
across the public internet. That's really the only conclusion I can
see here. Perhaps whats going on is that Microsoft can turn off the
NETBIOS protocol by default in the OS being install and this causes
lookup problems when the machine is not fully qualify possible.
--
HLS
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