LinuxQuestions.org
Register a domain and help support LQ
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Server
User Name
Password
Linux - Server This forum is for the discussion of Linux Software used in a server related context.

Notices



Reply
 
Search this Thread
Old 03-03-2009, 03:25 PM   #1
carlosinfl
Senior Member
 
Registered: May 2004
Location: Orlando, FL
Distribution: Arch
Posts: 2,905

Rep: Reputation: 73
Postfix Queue


I am noticing that for some reason everytime a specific user on my domain attempts to email a particular domain, the messages are always queued up. They don't ever appear to send for some reason and I checked the logs which don't really give any specific reason why I can't send email to this domain. Do you guys know by looking at what I can see on my end if this problem is caused by something on my end?

Code:
mail:~# postqueue -p
-Queue ID- --Size-- ----Arrival Time---- -Sender/Recipient-------
4DB191FA4D50    84627 Mon Mar  2 14:59:56  me@mydomain.com
             (connect to je.jfcom.mil[140.32.76.138]:25: Connection timed out)
                                         user1@je.jfcom.mil
                                         user3@je.jfcom.mil
                                         user5@je.jfcom.mil

557E41FA4D30    84155 Mon Mar  2 08:19:14  me@mydomain.com
             (connect to je.jfcom.mil[140.32.76.138]:25: Connection timed out)
                                         user1@je.jfcom.mil
                                         user2@je.jfcom.mil
                                         user3@je.jfcom.mil

CFD8F1FA4D4E    84627 Mon Mar  2 14:59:55  me@mydomain.com
    (connect to smtpva01.atec.army.mil[147.241.1.18]:25: Connection timed out)
                                         user@atec.army.mil
       (connect to wsgw1.atc.army.mil[134.194.13.55]:25: Connection timed out)
                                         user@atc.army.mil

C9EA81FA4D33    84155 Mon Mar  2 08:19:15  me@mydomain.com
        (connect to smtpva01.atec.army.mil[147.241.1.18]:25: No route to host)
                                         user@atec.army.mil
       (connect to wsgw2.atc.army.mil[134.194.13.56]:25: Connection timed out)
                                         user@atc.army.mil

054741FA4D55     2029 Mon Mar  2 12:16:04  me@mydomain.com
             (connect to je.jfcom.mil[140.32.76.138]:25: Connection timed out)
                                         user@je.jfcom.mil

-- 352 Kbytes in 5 Requests.
 
Old 03-03-2009, 05:40 PM   #2
dkm999
Member
 
Registered: Nov 2006
Location: Seattle, WA
Distribution: Fedora
Posts: 407

Rep: Reputation: 35
There are a couple of possibilities here:
1. You are trying to send mail to a non-existent host
2. You are trying to send mail to a host that is ignoring you.

I used nslookup to verify the address your queue is showing, and it does correspond to je.jfcom.mil. But a request for the mail-exchangers for jfcom.mil does not indicate that this host should be receiving mail. The mail-exchangers for that domain are
Code:
smtp01.jfcom.mil
smtp02.jfcom.mil
So this problem resolves into a new one: how did your Postfix come up with the name je.jfcom.mil to send messages to? Did the user explicitly specify that host as a target? Or did Postfix get bad info from its DNS lookup of MX records? Or did something else happen to misdirect these messages? Only a good look at the mail headers for the offending messages will tell you that. When a message finally expires and is sent back to its originator (or to the postmaster), you will need to examine the headers to see at what stage of forwarding a host made the choice to use the wrong mail exchanger. Then further work will be needed to figure out why.

Good luck.
 
Old 03-04-2009, 09:30 AM   #3
carlosinfl
Senior Member
 
Registered: May 2004
Location: Orlando, FL
Distribution: Arch
Posts: 2,905

Original Poster
Rep: Reputation: 73
When I go to my Postfix email server, I checked to see what it resolves as follows:

Code:
mail:~# host je.jfcom.mil
je.jfcom.mil        	A	140.32.76.138
I then ran the same command against what you noted above are the correct mail exchanges for that domain:

Code:
mail:~# host smtp01.jfcom.mil
smtp01.jfcom.mil    	A	199.112.135.44
It appears that address is totally different. What do you think is the problem here? I don't understand...
 
Old 03-04-2009, 02:20 PM   #4
dkm999
Member
 
Registered: Nov 2006
Location: Seattle, WA
Distribution: Fedora
Posts: 407

Rep: Reputation: 35
As you discovered, there are correct resolutions for the names of both hosts, so that is not a problem. But in order to accept mail for delivery, je.jfcom.mil would have to be listening on TCP port 25, which it very likely is not doing, either because it has been configured not to accept mail, or because there is an intervening firewall that is preventing it from hearing your request.

Postfix (and other mail-transfer agents) follows this protocol in sending mail.

1. Look for a DNS MX record for the specific host (not an A record).
2. If that is found, use it. Otherwise, lop off the leading part of the DNS name, and look for a DNS MX record for the subdomain.
3. Continue this process until an MX record is found.

In this case, the correct process would be to look first for an MX record for je.jfcom.mil. When that fails, the next step should be to look for an MX record for jfcom.mil. If that fails, look for one for .mil, which will probably fail as well, since it is pretty unlikely that anyone would offer to accept mail for an entire top-level domain.

This process can be complicated by the fact that mail-transfer agents cache previously-used MX records, and will use them if nothing else is found.

So, in your case, I recommend that you check if your resolver can deliver the correct MX record when asked
Code:
#nslookup
set type=mx
je.jfcom.mil
{should time out}
jfcom.mil
{should report 2 MX records}
This test will eliminate local DNS problems as a source for the deferral you first reported. Then, as I suggested in my previous post, examine the mail headers when the e-mail finally bounces to see where the message has gone, and how it was directed for further clues as to what has gone wrong.
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Postfix Email Is Stuck In Queue carlosinfl Linux - Server 3 06-19-2008 11:19 PM
Postfix Mail queue high inaki Linux - Software 3 02-13-2008 04:23 AM
Postfix - know queue size shritesh Linux - Software 1 03-17-2007 10:38 AM
Postfix on RH 9 'No Recipient' in queue rangert Linux - Server 3 10-25-2006 12:57 PM
Postfix Queue And Relay shritesh Linux - Server 0 10-06-2006 08:01 AM


All times are GMT -5. The time now is 04:54 PM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
identi.ca: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration