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  • Trouble receiving emails from some senders

    Hi all,
    This is my first post here and I hope you will forgive me for what is a long one. I have tried to give as much detail as I can.

    Over the past few months, I have noticed that emails from some senders are not making it through to me. I couldnít state for sure when it first happened but I had a few events back in April / May when it may have started:
    I am using Exchange 2010 SP1 on Windows 2008R2 with Forefront 2010. I receive email on two domains.

    In April, Forefront stopped working and I had to reinstall.
    In May, I upgraded to FTTC broadband, but kept the same ISP and static IP address. Network equipment is Huwai modem and Netgear WNDR3800 router.

    I noticed that emails from my father (in particular) were not getting through and finally my wife started to complain too. If he copied my work email address at the same time, they did get through. I logged onto his webmail and was able to send emails which Exchange could receive. Today, I created my own email address in his account and using Outlook via SMTP.POP3, mails I send to my Exchange donít get through. We tried at the weekend and added delivery reports. After a while, he got a 4.4.0 Other network problem '[Errno 60] Operation timed out'. Much of the time, no such messages are received. Itís intriguing that a webmail mail can get through to me, but an Outlook one cannot.

    I noticed that mails from other ISP domains donít seem to arrive either. Hotmail / Gmail does, as do those from this forum.

    I found Exchange SP3 and added that as well as the rollup 2. I have removed Forefront and disabled all Antispam. Iím getting plenty of that in now.

    I checked the firewalls and ports 25 and 587 are open and in the router, they are set to forward to the server.

    Anyone have any ideas about what I might try next?
    Many thanks
    Graham

  • #2
    Re: Trouble receiving emails from some senders

    First - Exchange 2010 SP1 is no longer supported. You need to upgrade to Exchange 2010 SP2, or preferably SP3 to be in a supported configuration.

    Do you see the connection attempts in the Receive Logs?
    Could be an issue with the router - has the firmware been upgraded? Not been a fan of the more recent Netgear kit, they have been stripping features out. My preference now is the Draytek.

    There should be no difference between an external webmail email and an Outlook email, they are both coming over SMTP.

    Have you checked your SSL certificates are valid?
    Run the best practises tool?

    I would also suggest the inbound email test at the Microsoft test site: http://exrca.com/

    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


    • #3
      Re: Trouble receiving emails from some senders

      Hi Simon,

      Many thanks for your response. I have upgraded to SP3 and installed rollup 2 as well.

      I'm not seeing anything in the receive logs, so I had been wondering whether the router is playing up. I must admit that having gone for many years with an early DG834, which worked just fine, I thought the newer router would do the job. In anticipation of an earlier FTTC upgrade, I put the newer router between the old and the ADSL line, and it seemed to work well. When it became the only router, it seems to perform less well. So perhaps a new router is in order. I will look at the Draytek.

      I checked the SSL Certificates and although self-signed, they are valid.

      The Microsoft Tool has no problems at all.

      It's odd that the one ISP I can check can get an email through from webmail, but not Outlook. I guess they must use different SMTP systems and one is more sensitive than the other.

      I ran the Best Practise Analyser and it found a few issues, but nothing to indicate that it would prevent the receipt of emails. Most do get through; itís just a few which donít and of course with them, they are the ones I want.

      I guess it is time to look at a new router

      Thanks
      Graham

      Comment


      • #4
        Re: Trouble receiving emails from some senders

        "I checked the SSL Certificates and although self-signed, they are valid."

        You have contradicted yourself there.

        Self Signed certificates aren't really valid for use on the internet - because anything outside your network doesn't trust them. That can cause delivery problems in some scenarios - particularly if the remote site wants to use TLS for delivery.

        While you will still need to use a self signed SSL certificate, given the high dependence on SSL and web services by the later versions of Exchange, a trusted SSL certificate is almost mandatory.

        Email delivery isn't reliable when it comes to it, and as the receiver, until the message is actually handed to your server you have no control over it. Only the sender can track what is happening to the messages.

        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


        • #5
          Re: Trouble receiving emails from some senders

          I'll have a look for a trusted certificate. It seems a little funny that it has worked for years with a self-signed, but these things happen. I looked at a couple of checkers for TLS and they both seemed happy enough that I could use TLS and I noticed that the notifications from the forum seem to use TLS - if I read the header correctly. But I will still investigate. Would I get an NDR if the sending SMTP server tried and failed to use TLS. I get the 4.4.0 timeout, but nothing more.

          I tried moving the server into my router's DMZ. That doesn't seem to have made any difference. I'll move it back.

          Here's another intriguing thing. I just added the account I created on the ISP to my iPad and did a test from there and the mail got through to me with no problems. So it almost seems that under certain circumstances Outlook cannot get a mail through. I sent the same mail to my work address and it got through and didn't appear to be using TLS. I forwarded that mail as an attachment to myself and my work email does use TLS. So there is definitely something funny going on.

          Thanks
          Graham

          Comment


          • #6
            Re: Trouble receiving emails from some senders

            Hi
            I have done some further investigation. I cleared my router logs and sent a test email from the ISP account using both the iPad and Outlook. Both seemed to get through the router.

            I then enabled Pipeline Tracing on that email address. When I send from the iPad, I get the Original.EML and then a bunch of Routing.EML and SMTPReceive.EML files. If I send using Outlook, I just get the Original.EML and nothing else.

            Any suggestions as to where to look next?

            Thanks
            Graham

            Comment

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