Strange MX Record for altavista.com

[Three Letter Acronym]

Mark Andrews wrote:
>>There is a mail system here that has mail queued for altavista.com.
>>dig reports:
>>
>>atalanta% dig altavista.com mx
>>
>>     ; <<>> DiG 8.3 <<>> altavista.com mx 
>>     ;; res options: init recurs defnam dnsrch
>>     ;; got answer:
>>     ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4
>>     ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 5, ADDITIONAL: 0
>>     ;; QUERY SECTION:
>>     ;;      altavista.com, type = MX, class = IN
>>     
>>     ;; ANSWER SECTION:
>>     altavista.com.          10M IN MX       0 .
>>     

[snip]

>>That is a strange MX record.  When that mail system (MX Exchange)
>>tries to send the mail, it opens an SMTP port 25 connection to one of
>>my DNS servers.  Is this what is supposed to happen?  Thanks.

[snip]

> 	It's an attempt to say "don't sent mail to the domain
> 	altavista.com."  It's a pity it is not been codified
> 	AFAIK.
> 
> 	I would be teaching my MTA to treat a MX record like
> 	this as a indication to just bounce the mail.
> 

Note that altavista.com uses SPF to declare that they don't send any 
mail either...

		--eli

dart at laptop ~ >> dig txt altavista.com

; <<>> DiG 9.2.3 <<>> txt altavista.com
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 54292
;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 5, ADDITIONAL: 0

;; QUESTION SECTION:
;altavista.com.                 IN      TXT

;; ANSWER SECTION:
altavista.com.          587     IN      TXT     "Null SPF is for 
tracking purposes only"
altavista.com.          587     IN      TXT     "All mail claiming to be 
from altavista.com is forged"
altavista.com.          587     IN      TXT     "v=spf1 
+exists:CL.%{i}.FR.%{s}.HE.%{h}.null.spf.altavista.com -all"
altavista.com.          587     IN      TXT     "This domain sends no email"