[sf-lug] resolver problem

Sat Aug 18 18:50:40 PDT 2012

I'm not sure I completely understand but it appears that dig can be told to look for a specific service and your failure of dig -t mx indicates that mailout.easydns.com doesn't have the needed service. 
As it turns out, use of mailout.easydns.com works on another plug computer that I run on another network and the dig -t mx fails there as well.
The mystery remains unsolved. 
Here's the evidence:
alex at www:~$ dig -t mx mailout.easydns.com +short
alex at www:~$ dig  mailout.easydns.com +short
64.68.200.141
alex at www:~$ dig -p 2025 -t mx mailout.easydns.com +short

; <<>> DiG 9.7.3 <<>> -p 2025 -t mx mailout.easydns.com +short
;; global options: +cmd
;; connection timed out; no servers could be reached
alex at www:~$ dig mailout.easydns.com +short
64.68.200.141
alex at www:~$ dig -p2025 mailout.easydns.com +short
; <<>> DiG 9.7.3 <<>> -p2025 mailout.easydns.com +short

;; global options: +cmd

;; connection timed out; no servers could be reached

I haven't mentioned that mailout.easydns.com listens on an unconventional port and I thought that might be an explanation for the dig -t mx failure but it seems not.
I have postfix running on both machines with the same /etc/postfix/main.cf file (except for the "mydestination=" line)

alex

--- On Sat, 8/18/12, Tom Haddon <tom at greenleaftech.net> wrote:

From: Tom Haddon <tom at greenleaftech.net>
Subject: Re: [sf-lug] resolver problem
To: sf-lug at linuxmafia.com
Date: Saturday, August 18, 2012, 9:10 AM

    You're mixing things that you're
      checking here. The host DNS entry for mailout.easydns.com may
      exist, but that doesn't mean there's an MX record for it.

      mthaddon at mallory:~$ dig mailout.easydns.com

      ; <<>> DiG 9.8.1-P1 <<>>
      mailout.easydns.com

      ;; global options: +cmd

      ;; Got answer:

      ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id:
      53568

      ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL:
      0

      ;; QUESTION SECTION:

      ;mailout.easydns.com.        IN    A

      ;; ANSWER SECTION:

      mailout.easydns.com.    300    IN    A    64.68.200.141

      ;; Query time: 12 msec

      ;; SERVER: 127.0.0.1#53(127.0.0.1)

      ;; WHEN: Sat Aug 18 17:09:43 2012

      ;; MSG SIZE  rcvd: 53

      mthaddon at mallory:~$
      dig -t mx mailout.easydns.com

      ; <<>> DiG 9.8.1-P1 <<>> -t mx
      mailout.easydns.com

      ;; global options: +cmd

      ;; Got answer:

      ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id:
      42943

      ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL:
      0

      ;; QUESTION SECTION:

      ;mailout.easydns.com.        IN    MX

      ;; Query time: 13 msec

      ;; SERVER: 127.0.0.1#53(127.0.0.1)

      ;; WHEN: Sat Aug 18 17:04:57 2012

      ;; MSG SIZE  rcvd: 37

      Looks like you need to double check that that's what you should be
      trying to connect to.

      Thanks, Tom

      On 18/08/12 16:55, Alex Kleider wrote:

            I've got postfix
              installed on my DreamPlug and am trying to get it

              configured to be able to send mail out to a "smart host."
              The smart host is

              mailout.easydns.com.  Mail doesn't get out; the following
              is reported

              in /var/log/mail.info:

              """

              Aug 18 08:34:59 dp4 postfix/pickup[25907]: 36C8229CE7:
              uid=0 from=<root>

              Aug 18 08:34:59 dp4 postfix/cleanup[26005]: 36C8229CE7:

              message-id=<20120818153459.GA25992 at kleider.ca>

              Aug 18 08:34:59 dp4 postfix/qmgr[17065]: 36C8229CE7:

              from=<root at kleider.ca>, size=416, nrcpt=1 (queue
              active)

              Aug 18 08:35:15 dp4 postfix/smtp[26008]: 36C8229CE7:

              to=<akleider at sonic.net>, relay=none, delay=16,
              delays=0.1/0.03/16/0,

              dsn=4.4.3, status=deferred (Host or domain name not found.
              Name service

              error for name=mailout.easydns.com type=MX: Host not
              found, try again)

              """

              Investigation of name resolution gives what seem to be
              conflicting

              results (ping and dig work but traceroute and mtr don't):

              root at dp4:/var/log# ping mailout.easydns.com

              PING mailout.easydns.com (64.68.200.141) 56(84) bytes of
              data.

              64 bytes from mailout.easydns.com (64.68.200.141):
              icmp_req=1 ttl=50

              time=81.9 ms

              64 bytes from mailout.easydns.com (64.68.200.141):
              icmp_req=2 ttl=50

              time=79.9 ms

              64 bytes from mailout.easydns.com (64.68.200.141):
              icmp_req=3 ttl=50

              time=81.3 ms

              ^C64 bytes from mailout.easydns.com (64.68.200.141):
              icmp_req=4 ttl=50

              time=80.3 ms

              --- mailout.easydns.com ping statistics ---

              4 packets transmitted, 4 received, 0% packet loss, time
              13907ms

              rtt min/avg/max/mdev = 79.989/80.931/81.988/0.788 ms

              root at dp4:/var/log# traceroute mailout.easydns.com

              mailout.easydns.com: No address associated with hostname

              Cannot handle "host" cmdline arg `mailout.easydns.com' on
              position 1 (argc

              1)

              root at dp4:/var/log# dig @127.0.0.1 mailout.easydns.com

              ; <<>> DiG 9.7.3 <<>> @127.0.0.1
              mailout.easydns.com

              ; (1 server found)

              ;; global options: +cmd

              ;; Got answer:

              ;; ->>HEADER<<- opcode: QUERY, status:
              NOERROR, id: 47312

              ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0,
              ADDITIONAL: 0

              ;; QUESTION SECTION:

              ;mailout.easydns.com.           IN      A

              ;; ANSWER SECTION:

              mailout.easydns.com.    191     IN      A      
              64.68.200.141

              ;; Query time: 4016 msec

              ;; SERVER: 127.0.0.1#53(127.0.0.1)

              ;; WHEN: Sat Aug 18 08:27:38 2012

              ;; MSG SIZE  rcvd: 53

              root at dp4:/var/log# mtr mailout.easydns.com

              No address associated with hostname: Success

              Other commands that require resolver success (wget, w3m)
              work fine.

              Any thoughts?

              Alex

              ~           

              a_kleider at yahoo.com

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