Is anyone aware of any missing TLDs?
(defcustom message-valid-fqdn-regexp
(concat "[a-z0-9][-.a-z0-9]+\\." ;; [hostname.subdomain.]domain.
;; valid TLDs:
"\\([a-z][a-z]" ;; two letter country TDLs
"\\|biz\\|com\\|edu\\|gov\\|int\\|mil\\|net\\|org"
"\\|aero\\|coop\\|info\\|name\\|museum"
"\\|arpa\\|pro\\|uucp\\|bitnet\\|bofh" ;; old style?
"\\)")
"Regular expression that matches a valid FQDN."
;; see also: gnus-button-valid-fqdn-regexp
:version "22.1"
:group 'message-headers
:type 'regexp)
You can customize the variable!
BTW, the tin newsreader even hard-codes a matrix of (in)valid
two letter country domains. The user/admin has to recompile to add new
domains. IIRC it's used when checking for a valid FQDN.
This argument can be used in the reverse direction too. Do most
users really gain something from the list of known TLD:s in the
regexp?
For the purpose in Gnus: Yes, IMHO. What would you suggest to use
instead?
I wasn't joking. :-) Of course not from the format, but...
Basically you need to do something like "host -t mx" (using
`dig.el'?), connect to the smtp port, send "RCPT TO:" and parse the
output ("user unknown"?). But I'm not sure if this still works
nowadays.
Bye, Reiner.