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 |
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 Good luck. |
When I go to my Postfix email server, I checked to see what it resolves as follows:
Code:
mail:~# host je.jfcom.mil Code:
mail:~# host smtp01.jfcom.mil |
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 |
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