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  3. 🤔 Cloudron External SMTP > Mail-in-a-box SMTP > ECONNREFUSED

🤔 Cloudron External SMTP > Mail-in-a-box SMTP > ECONNREFUSED

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relayemailsmtp
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    • tshirt-chihuahuT Offline
      tshirt-chihuahuT Offline
      tshirt-chihuahu
      wrote on last edited by girish
      #1

      Attempting to setup an external email relay on Cloudron via an external SMTP server (which is a self-hosted instance of Mail-in-a-Box https://mailinabox.email/ in this case).

      This SMTP server works fine for email clients via SMTP connection.

      However, when I've attempted to connect to it from my Cloudron instance (Cloudron-Mautic app, now the default mail server), have had issues. Which makes me think it's on Cloudron's side.

      Incoming mail is disabled on Cloudron server.
      Attempted to change the Cloudron global mail server location to the SMTP server's domain. Didn't make any difference.
      Problem definitely is not the password.

      The Mail-in-a-box/SMTP server lives at box.domain.com.
      The cloudron instance is setup at my.domain.com via wildcard domain configuration in cloudron. (Visiting these servers via webpage works fine, so don't see any reason why this would be problematic.)
      Again, other SMTP connections to this Mail-in-a-box server work fine.

      The error message i'm getting is below ("ECONNREFUSED")

      Any ideas anyone?
      Thanks for the help.

      10e3d68e-959b-4658-9a6c-96f173c5822a-image.png

      tshirt-chihuahuT 1 Reply Last reply
      0
      • tshirt-chihuahuT tshirt-chihuahu

        Attempting to setup an external email relay on Cloudron via an external SMTP server (which is a self-hosted instance of Mail-in-a-Box https://mailinabox.email/ in this case).

        This SMTP server works fine for email clients via SMTP connection.

        However, when I've attempted to connect to it from my Cloudron instance (Cloudron-Mautic app, now the default mail server), have had issues. Which makes me think it's on Cloudron's side.

        Incoming mail is disabled on Cloudron server.
        Attempted to change the Cloudron global mail server location to the SMTP server's domain. Didn't make any difference.
        Problem definitely is not the password.

        The Mail-in-a-box/SMTP server lives at box.domain.com.
        The cloudron instance is setup at my.domain.com via wildcard domain configuration in cloudron. (Visiting these servers via webpage works fine, so don't see any reason why this would be problematic.)
        Again, other SMTP connections to this Mail-in-a-box server work fine.

        The error message i'm getting is below ("ECONNREFUSED")

        Any ideas anyone?
        Thanks for the help.

        10e3d68e-959b-4658-9a6c-96f173c5822a-image.png

        tshirt-chihuahuT Offline
        tshirt-chihuahuT Offline
        tshirt-chihuahu
        wrote on last edited by
        #2

        Realized this is most likely a firewall issue at this point.

        Saw some posts about Mautic (which I was previously attempting to connect directly to the same SMTP server via the app settings) configuration not behaving well - which I definitely experienced, which likely landed the IP on a block list.

        But if anyone else has any ideas I'd be happy to hear them.....

        girishG 1 Reply Last reply
        0
        • tshirt-chihuahuT tshirt-chihuahu

          Realized this is most likely a firewall issue at this point.

          Saw some posts about Mautic (which I was previously attempting to connect directly to the same SMTP server via the app settings) configuration not behaving well - which I definitely experienced, which likely landed the IP on a block list.

          But if anyone else has any ideas I'd be happy to hear them.....

          girishG Offline
          girishG Offline
          girish
          Staff
          wrote on last edited by girish
          #3

          @tshirt-chihuahu It seems that for some reason the SMTP host resolves to 127.0.1.1 (from the error message). Can you try to run host box.domain.com on the Cloudron server and tell me what it returns?

          (Also, do you have any custom DNS setup by any chance?)

          tshirt-chihuahuT 1 Reply Last reply
          0
          • girishG girish

            @tshirt-chihuahu It seems that for some reason the SMTP host resolves to 127.0.1.1 (from the error message). Can you try to run host box.domain.com on the Cloudron server and tell me what it returns?

            (Also, do you have any custom DNS setup by any chance?)

            tshirt-chihuahuT Offline
            tshirt-chihuahuT Offline
            tshirt-chihuahu
            wrote on last edited by tshirt-chihuahu
            #4

            @girish good point. here's what is returned on the cloudron server at my.domain.com:

            $ host box.domain.com
            box.domain.com has address [correct IP address for MIAB machine]
            box.domain.com mail is handled by 10 box.domain.com

            [correct ip address for MIAB machine] is of course definitely not 127.0.1.1

            re: custom DNS
            the Mail-in-a-Box server at box.domain.com controls the DNS for domain.com and otherdomain.com (standard for MIAB to control DNS) and there are custom DNS entries....

            However, the only custom DNS records are the wildcard A records (1 for each domain) pointing to the same cloudron server.

            Thus the "host" command on the cloudron machine returns the expected IP addresses for the Cloudron and MIAB servers based on the domain/subdomain pinged.

            Host is Vultr in case that provides any clues. The servers are in the same geographic location listed by Vultr.

            My current hypotheses (which likely aren't worth much):

            • Error message is not returning the expected information (has happened before will happen again)
            • there's something going on with the container isolation strategy you guys are using that isn't playing nicely with the network.... but you'd know way more about that than me.

            I'm going to run with the firewall idea to see if that leads to a fix so that can be counted out and will report back.

            girishG tshirt-chihuahuT 2 Replies Last reply
            0
            • tshirt-chihuahuT tshirt-chihuahu

              @girish good point. here's what is returned on the cloudron server at my.domain.com:

              $ host box.domain.com
              box.domain.com has address [correct IP address for MIAB machine]
              box.domain.com mail is handled by 10 box.domain.com

              [correct ip address for MIAB machine] is of course definitely not 127.0.1.1

              re: custom DNS
              the Mail-in-a-Box server at box.domain.com controls the DNS for domain.com and otherdomain.com (standard for MIAB to control DNS) and there are custom DNS entries....

              However, the only custom DNS records are the wildcard A records (1 for each domain) pointing to the same cloudron server.

              Thus the "host" command on the cloudron machine returns the expected IP addresses for the Cloudron and MIAB servers based on the domain/subdomain pinged.

              Host is Vultr in case that provides any clues. The servers are in the same geographic location listed by Vultr.

              My current hypotheses (which likely aren't worth much):

              • Error message is not returning the expected information (has happened before will happen again)
              • there's something going on with the container isolation strategy you guys are using that isn't playing nicely with the network.... but you'd know way more about that than me.

              I'm going to run with the firewall idea to see if that leads to a fix so that can be counted out and will report back.

              girishG Offline
              girishG Offline
              girish
              Staff
              wrote on last edited by
              #5

              @tshirt-chihuahu said in 🤔 Cloudron External SMTP > Mail-in-a-box SMTP > ECONNREFUSED:

              Thus the "host" command on the cloudron machine returns the expected IP addresses for the Cloudron and MIAB servers based on the domain/subdomain pinged.

              Can you try host box.domain.com 127.0.0.1 as well ? Cloudron has an internal DNS server (called unbound). Depending on whether the host command works, you might have to tweak that DNS for your setup - https://docs.cloudron.io/networking/#private-dns

              tshirt-chihuahuT 1 Reply Last reply
              0
              • girishG girish

                @tshirt-chihuahu said in 🤔 Cloudron External SMTP > Mail-in-a-box SMTP > ECONNREFUSED:

                Thus the "host" command on the cloudron machine returns the expected IP addresses for the Cloudron and MIAB servers based on the domain/subdomain pinged.

                Can you try host box.domain.com 127.0.0.1 as well ? Cloudron has an internal DNS server (called unbound). Depending on whether the host command works, you might have to tweak that DNS for your setup - https://docs.cloudron.io/networking/#private-dns

                tshirt-chihuahuT Offline
                tshirt-chihuahuT Offline
                tshirt-chihuahu
                wrote on last edited by tshirt-chihuahu
                #6

                @girish said in 🤔 Cloudron External SMTP > Mail-in-a-box SMTP > ECONNREFUSED:

                host box.domain.com 127.0.0.1

                This returns:

                Using domain server:
                Name: 127.0.0.1
                Address: 127.0.0.1#53
                Aliases:

                box.domain.com has address [MIAB Server IP]
                box.domain.com mail is handled by 10 box.domain.com

                I assume this is as expected/desired, correct?

                tshirt-chihuahuT 1 Reply Last reply
                0
                • tshirt-chihuahuT tshirt-chihuahu

                  @girish good point. here's what is returned on the cloudron server at my.domain.com:

                  $ host box.domain.com
                  box.domain.com has address [correct IP address for MIAB machine]
                  box.domain.com mail is handled by 10 box.domain.com

                  [correct ip address for MIAB machine] is of course definitely not 127.0.1.1

                  re: custom DNS
                  the Mail-in-a-Box server at box.domain.com controls the DNS for domain.com and otherdomain.com (standard for MIAB to control DNS) and there are custom DNS entries....

                  However, the only custom DNS records are the wildcard A records (1 for each domain) pointing to the same cloudron server.

                  Thus the "host" command on the cloudron machine returns the expected IP addresses for the Cloudron and MIAB servers based on the domain/subdomain pinged.

                  Host is Vultr in case that provides any clues. The servers are in the same geographic location listed by Vultr.

                  My current hypotheses (which likely aren't worth much):

                  • Error message is not returning the expected information (has happened before will happen again)
                  • there's something going on with the container isolation strategy you guys are using that isn't playing nicely with the network.... but you'd know way more about that than me.

                  I'm going to run with the firewall idea to see if that leads to a fix so that can be counted out and will report back.

                  tshirt-chihuahuT Offline
                  tshirt-chihuahuT Offline
                  tshirt-chihuahu
                  wrote on last edited by
                  #7

                  @girish

                  I'm going to run with the firewall idea to see if that leads to a fix so that can be counted out and will report back.

                  Doesn't appear to be a firewall issue afterall. Nothing on the ban list (fail2ban) now and issue persists.

                  1 Reply Last reply
                  0
                  • tshirt-chihuahuT tshirt-chihuahu

                    @girish said in 🤔 Cloudron External SMTP > Mail-in-a-box SMTP > ECONNREFUSED:

                    host box.domain.com 127.0.0.1

                    This returns:

                    Using domain server:
                    Name: 127.0.0.1
                    Address: 127.0.0.1#53
                    Aliases:

                    box.domain.com has address [MIAB Server IP]
                    box.domain.com mail is handled by 10 box.domain.com

                    I assume this is as expected/desired, correct?

                    tshirt-chihuahuT Offline
                    tshirt-chihuahuT Offline
                    tshirt-chihuahu
                    wrote on last edited by
                    #8

                    @girish
                    Given it doesn't appear to be a DNS issue as box.domain.com 127.0.0.1 routes to the mail server. Any other ideas? I'm stuck.

                    girishG 1 Reply Last reply
                    0
                    • tshirt-chihuahuT tshirt-chihuahu

                      @girish
                      Given it doesn't appear to be a DNS issue as box.domain.com 127.0.0.1 routes to the mail server. Any other ideas? I'm stuck.

                      girishG Offline
                      girishG Offline
                      girish
                      Staff
                      wrote on last edited by
                      #9

                      @tshirt-chihuahu The DNS response seems correct. So, the issue is somewhere else. Let me quickly test it here to see if it's a general issue or something with your setup.

                      1 Reply Last reply
                      0
                      • girishG Offline
                        girishG Offline
                        girish
                        Staff
                        wrote on last edited by
                        #10

                        The root cause for this was the Cloudron server had the hostname as "box.domain.com" (same as the relay). Debian/Ubuntu has a quirk that it will put the hostname in /etc/hosts to resolve as 127.0.1.1. This meant that when we try to set it as relay, it resolves to 127.0.1.1 instead of the actual IP.

                        To add to the confusion, I suggested using the host command which does not use /etc/hosts (i.e the nsswitch mechanisms) and uses only the DNS. If I had suggested using ping then we would have narrowed down the issue more quickly...

                        Anyway, the fix is simply to hostnamectl set-hostname somethingelse.domain.com and also edit /etc/hosts (for some reason, hostnamectl doesn't change hosts file even after reboot, 🤷 ).

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