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  • No external emails

    As most thread starters, I hope someone can help.I recently migrated from windows sbs 2003 to a new sbs 2008 server, will little problems. Emails were working fine incoming and outgoing. Yesterday morning, all external emails stopped coming in. All internal emails are still fine from all users and emails outgoing are fine also.I can l telnet localhost 25 no problems but I cannot telnet either the ip address or the via the name. The mail flow trouble shooter shows no errors. Seems to me that the exchange is fine but the outside world suddenty cannot find my exchange server. Port forwarding is correct on the router. Only thing I can think of other than that is the DNS but I am unsure on where to beging?Appreciate any feedback.

  • #2
    Re: No external emails

    Use the Microsoft Exchange Remove Connectivity Analyzer to run the Inbound SMTP test. That should give you a clue where the issue is.

    https://testexchangeconnectivity.com/

    Eg it will tell you if DNS is failing, or the port is closed.

    If you can telnet from a workstation to the Exchange server on port 25, but not from outside the firewall, it may be your firewall playing up. I've also seen issues where the ISP is applying their own filtering of inbound SMTP, though this is usually on home/consumer connections not business services.

    If you can't telnet from a workstation on the LAN to the Exchange server, check the Windows Firewall on the server, and also check for other client security apps such as antivirus software that sometimes blocks port 25.
    Blog: ExchangeServerPro.com
    Twitter: @ExchServPro

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    • #3
      Re: No external emails

      Thanks Paul for your reply.

      Tested using the link you provided and recieved this error -

      A network error occurred while communicating with the remote host.
      Exception details:
      Message: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond xxx.xxx.xxx.xxx:25
      Type: System.Net.Sockets.SocketException
      Stack trace:
      at System.Net.Sockets.TcpClient.Connect(String hostname, Int32 port)
      at Microsoft.Exchange.Tools.ExRca.Tests.TcpPortTest.P erformTestReally()

      So it appears that exchange is either not listening or the port is blocked.
      I dont believe that the ISP have blocked the port as it was working a couple of days ago but will check to be sure.
      There was a problem with self signed signatures when the cut over was first done. Could this be part of the problem? I need to purchase a 3rd party certificate, but I am unsure where to start. Apologies for my naivity

      Comment


      • #4
        Re: No external emails

        I'm not sure whether you've also tested telnet from a workstation on your LAN to the Exchange server. Can you confirm that please?

        No you don't need to worry about certs for SMTP scenarios like this.
        Blog: ExchangeServerPro.com
        Twitter: @ExchServPro

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        • #5
          Re: No external emails

          I've found SBS2008 firewall often blocks things like SMTP so as suggested try turning that off or adding a specific exclusion for port 25.

          Have you set any security on the connectors that might affect where they accept connections from?

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          • #6
            Re: No external emails

            you need to ensure that the open port 25 on the public interface correctly forwards to the correct IP address on the internal server....

            if you're sure your port forwarding is correct and you still get blocked, definitely speak to your ISP.


            test it by telnetting from your firewalll to port 25 on the mail server
            Please do show your appreciation to those who assist you by leaving Rep Point https://www.petri.com/forums/core/im.../icon_beer.gif

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            • #7
              Re: No external emails

              Originally posted by beddo View Post
              I've found SBS2008 firewall often blocks things like SMTP so as suggested try turning that off or adding a specific exclusion for port 25.

              Have you set any security on the connectors that might affect where they accept connections from?
              If you setup SBS 2008 using the wizards, then the firewall is configured correctly for inbound SMTP traffic. Disabling the firewall is not recommended, as it can actually cause problems due to the way it is integrated in to the network stack - that goes for all 2008 and higher server products.

              For an SBS 2008 system, run the Fix My Network wizard, which will ensure everything server side is working correctly, but if it was working and now isn't, that would tend to point to an issue outside of the server.

              Simon.
              --
              Simon Butler
              Exchange MVP

              Blog: http://blog.sembee.co.uk/
              More Exchange Content: http://exchange.sembee.info/
              Exchange Resources List: http://exbpa.com/
              In the UK? Hire me: http://www.sembee.co.uk/

              Sembee is a registered trademark, used here with permission.

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              • #8
                Re: No external emails

                I have actually done two SBS 2008 installs recently. Both were set up using the wizards and both had the firewall blocking SMTP inbound by default. I had to manually add TCP port 25 in the exclusion list, also the same with 3389 for RDP but everything else seemed fine.

                For the record, I was only advising to disable the firewall for testing.

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                • #9
                  Re: No external emails

                  Thanks for all the replies. Very much appreciated.So on the advice that has been given, I have done the followingTelnet from a workstation on the Lan - connects to the server OKDouble checked the port forwarding on the router - Port 25 is configuredJust for testing (willing to try anything) I dropped the firewall for a minute to test Telnet for both the intenet IP to my server and the name - Both unable to connectRun the fix my network wizard (where has that little puppy been all my life!) - Comes up with one error - DNS is using a DNS forwarderAny more suggestions gents? Hope this may shed some more light on where to look.

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                  • #10
                    Re: No external emails

                    Well I dont know if the "Fix my network" magic button did something behind the scenes or if it was further upstream but a million emails just started pooring in and I am able to telnet from outside the LAN. Thanks for your repsonses guys. But dont you just hate when you fix something and have no idea of the cause let alone what fixed it?

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                    • #11
                      Re: No external emails

                      That is often what the fix my network does - it makes the changes that you don't see in the background. On SBS it is always the first tool to use. Fab tool, resolves a lot of issues.

                      Simon.
                      --
                      Simon Butler
                      Exchange MVP

                      Blog: http://blog.sembee.co.uk/
                      More Exchange Content: http://exchange.sembee.info/
                      Exchange Resources List: http://exbpa.com/
                      In the UK? Hire me: http://www.sembee.co.uk/

                      Sembee is a registered trademark, used here with permission.

                      Comment


                      • #12
                        Re: No external emails

                        Fab tool is right. I was ready to unlawful things to M$.
                        Didn't even know it existed until you guys pointed it out for me.

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                        • #13
                          Re: No external emails

                          SBS mate - there's a wizard to do _Everything_
                          and everything should be done with the wizard...
                          Please do show your appreciation to those who assist you by leaving Rep Point https://www.petri.com/forums/core/im.../icon_beer.gif

                          Comment


                          • #14
                            Re: No external emails

                            I have learned now! As I bet you can tell I am new to the server side of things and got 'volunteered' for the job, on the 2003 server and now this upgrade. So I am still learning my way around 2008. Looking for wizards from now on!

                            Cheers again for the help gents. Was loosing sleep over this one...

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