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Unrouteable Mail, Backup MX & Troubleshooter

Discussion in 'E-mail Discussions' started by vinc_dc43, Jan 30, 2004.

  1. vinc_dc43

    vinc_dc43 Well-Known Member

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    I frequently look over the mail queues, as well as the statistsics, on all of my servers to inspect for various things.

    Right now I operate a primary server which hosts mail, dns and www and i have 2 over servers which act as backup MX and DNS servers, whilst I have a 4th server which is slowly being brought into commision and right now is only being tested.

    Anyhow!

    Today I was looking for the Q on server3 and found that it was having trouble doing remote_smtp on a certain domain. When I go to mail troubleshooter it shows the domain as unrouteable.

    As it stands I have the domain listed in the /etc/secondarymx and the /etc/remotedomains file, although other domains dont have this and work fine. I also recreated the DNS zone as this particular domain didn't have one and like 99% of the domains I host, its authorititive records are hosted at a third party dns service provider. I have WHM and CPANEL running @ release level and they update nightly. The /etc/localdomains file is empty aside from the server hostname. operating mail from an ssh root login seems to work, but for some reason exim and troubleshooter seem incapable of operating properly and forwarding/smtp'ing mails on towards the primary mail server for this domain.

    Right now I am kind of flumoxed. I even updated exim and ran the updates per peoples suggestions.

    I just wonder if anyone might have jad similar issues and whom might be able to enlighten me, because as yet nothing i have found on the forum has made that domain routeable for this specific server, which is one out of 4!

    Thanks in advance for any help.
     
  2. vinc_dc43

    vinc_dc43 Well-Known Member

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    progression ...

    Adding more info to my own post ...

    I dig a little deeper by running the following command:

    exim -bt -d user@domain.com

    where user@domain is a valid email address.

    when I run this on an email which doesn't work and one which does they come out with different results.

    On the ones that don't work it seems as if for that domain, for whatever reason the A records for the mx server addresses mx1, mx2 and mx3 are unresolveable. Where as for the email domain that works fine the MX records can be resolved to the respective ip addresses.

    I looked at the DNS records both on the servers and on the third party companies management tool and they all look identical

    The way I have the mx records set up is to point the domain1.com. @ mx1.domain2.com. pref 10 and so on.

    I don't understand how exim can resolve the mx server A records for one domain but not the other. I wonder if I need to change the resolv.conf files on all servers to match?

    Would this be an entirely DNS issue or would it more likelly be an entirely EXIM problem?

    Doing an DIG mx1.domain1.com -A command comes up empty on the secondary server that comes up with unrouteable email addresses where as on other servers it doesn't.
     
    #2 vinc_dc43, Jan 30, 2004
    Last edited: Jan 30, 2004
  3. vinc_dc43

    vinc_dc43 Well-Known Member

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    Some Kind of Solution

    well after trying various things and using dig and nslookup also I realised that the DNS server being used to determine the MX server records for the domain that wasn't working was for whatever reason returning wrong SOA records. This was resulting in errors. Apparently consistent errors!

    I fixed the problem by switching around the nameserver list in the /etc/resolv.conf file so that the two DNS servers listed at the top where ones that returned valid SOA records and thereofre the ip's for the related mx.domain.com records.

    Now of course when i go to check a domain for which I host the dns, trouble shootercomes up with what appears to be an error "in host list: removed host"

    is this a bug with troubleshooter?

    When i run the exim command on the same email it comes ok and sends. as does email sent to the domain from root.
     
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