inability to send email - who's problem?

[Barry Margolin]

In article <eple8r$8gn$1 at sf1.isc.org>,
 Dana Holland <dana.holland at navarrocollege.edu> wrote:

> We're having issues sending email to various domains - they are returned 
> with a message:
> 
> Hi. This is the DeskNow mail server at mail.navarrocollege.edu.
> I'm afraid I wasn't able to deliver your message to the following addresses.
> This is a permanent error; I've given up trying. Sorry it didn't work out.
> These recipients did not receive the message:
> ann at ipa.net
> 
> This is why I was unable to deliver your message:
> Remote mail server at 207.69.189.21 replied: 550 Authentication 
> required. Help at http://www.earthlink.net/go/emailsettings

For some reason you're not finding their MX records, so you're using 
their A records.  These points to the *outgoing* SMTP server, which only 
accepts mail from their customers, rather than the incoming MX servers.

I'm not sure what you could be doing that would allow you to look up the 
A records but not the MX records.  But I don't see any problem when I 
query the authoritative server myself.

> 
> 
> We see these messages when we try to send to ipa.net, mindspring.com, 
> and even earthlink.net.  We see them when trying to send to yahoogroups. 
>   And we even seen them when trying to mail to various state.tx.us 
> addresses.
> 
> A "dig ipa.net mx" returns:
> 
> ; <<>> DiG 9.2.4 <<>> ipa.net mx
> ;; global options:  printcmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 49491
> ;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 13, ADDITIONAL: 0

Why are you querying a server that has recursion disabled?

> 
> ;; QUESTION SECTION:
> ;ipa.net.                       IN      MX
> 
> ;; AUTHORITY SECTION:
> .                       518400  IN      NS      D.ROOT-SERVERS.net.
> .                       518400  IN      NS      E.ROOT-SERVERS.net.
> .                       518400  IN      NS      F.ROOT-SERVERS.net.
> .                       518400  IN      NS      G.ROOT-SERVERS.net.
> .                       518400  IN      NS      H.ROOT-SERVERS.net.
> .                       518400  IN      NS      I.ROOT-SERVERS.net.
> .                       518400  IN      NS      J.ROOT-SERVERS.net.
> .                       518400  IN      NS      K.ROOT-SERVERS.net.
> .                       518400  IN      NS      L.ROOT-SERVERS.net.
> .                       518400  IN      NS      M.ROOT-SERVERS.net.
> .                       518400  IN      NS      A.ROOT-SERVERS.net.
> .                       518400  IN      NS      B.ROOT-SERVERS.net.
> .                       518400  IN      NS      C.ROOT-SERVERS.net.
> 
> ;; Query time: 3 msec
> ;; SERVER: 205.165.189.183#53(205.165.189.183)
> ;; WHEN: Mon Jan 29 08:14:36 2007
> ;; MSG SIZE  rcvd: 233
> 
> Is this a DNS problem on my end, or on the other end?  We're running 
> bind 9.3.4.

-- 
Barry Margolin, barmar at alum.mit.edu
Arlington, MA
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