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  • Bad emails holding up and delaying Good emails

    Hi,
    Got a question about the queues in Exchange 2007.
    Recently, I was testing the email server and as usual, emails to yahoo, hotmail, etc, going through, no problems, but then emails go gmail taking 1 hour and 10 minutes do deliver?!?
    So i went through the email header and noticed that the largest delay is between the message being passed from our email server through our intrusion prevention device (Proventia). OK...kept on searching, etc...nothing...

    A day later we found out that one of the users has the forwarding enabled. We created an email id for him on exchange for his gmail and basically all emails he receives in his company inbox a copy also gets sent to his gmail. His gmail was full (yes, i congratulated him on this achievement - the first person i know who did this! ) . As i disabled his forwarding, suddenly all the messages went through in seconds to gmail.

    Now, i was looking through the queue again a few days later. And basically there are a couple of addresses in the queue that don't seem to be valid. So now it is taking about 7 or 8 minutes to deliver an email to gmail.

    So my question is how do i manage the queues in such situations? Is it normal for other (good) emails going to the same domain (such as gmail) to be stuck or blocked for some time because of the bad emails? Can i prevent this from happening? I'm getting worried that the exchange 2007 is doing a first in, first out sending queue order which would hold up the rest of the queue.

    Any input is welcome!

    many thanks.

  • #2
    Re: Bad emails holding up and delaying Good emails

    I don't think this is an Exchange problem. I have never seen Exchange work in the way that you have described. Each email is delivered independantly, unless you have done something with the connectors.

    You say that there are addresses in there that are bad. How did they get in there? Are they errors by users or something else?

    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: Bad emails holding up and delaying Good emails

      When I mean bad, in the sense that they are wrongly entered emails by users (typos) that do not exist (mis-spelling, dropping a letter, etc)...

      Am just looking at the exchange queue now...I've also sent my self an email from the company account to my private gmail account 3 minutes ago, still waiting for it. Sent myself an email to my hotmail account - instantenous. Currently, in the queue, all the messages are in the same queue id (excpet one). The one that is in a different queue is an email being sent by another user to a completely different domain and the status is active but when double click i get 451 internal error. This email is 5th out of 6 in a queue.

      The 6th message in the queue is to a gmail user, however has been there for past 4 hours with 421 4.4.2 connect dropped error and status as active. The 3rd and 4th message are also to gmail and have same error but statu is ready. They have been in the queue for the past 4 or 5 hours also.

      The mesage i just sent to my private gmail account is in status ready. So still waiting for it to come through (no errors).

      Finally, the first message in the queue is also to a gmail account in status ready and without errors.
      In the meantime i just noticed another user sent an email to another gmail account and it entered the queue at the bottom of the list (message number 7).

      As for the connectors, we got a single exchange server behind firewall (small company). Inside orgnaisation configuration, hub transport, when you click on send connectors tab, and double click on our (call it "company email") connector, when selecting address space tabs, type is SMTP, address is *, Cost is 1 (followed installation steps), the network tab i checked "use domain name system DNS "MX" records to route mail automatically, as well as selecting the check box at the bottom for "use the external dns lookup settings on the trasnport server".

      In the server configuration, hub trasnport, when we click on the "company" hub trasnport, for external dns lookups we selected use these DNS servers and we entered the ISP external public DNS servers (forwarders), in internal dns lookup, we selected use these dns servers and entered ip of our internal DNS.

      For the recieve connectors, we got one called client company and one called default company. In both, on the network tab use these local ip addresses to receive email there is ipv4 and ipv6 but on the default it is port 25 and one the client company it is port 587, and receive mail from remote servers that these ip addresses 0.0.0.0-255.255.255.255.
      On the default company authentication, the transport layer security, basic authentication, offer basic authentication after starting TLS, exchange server authentication, integrated windows authentication boxes are all checked. Permissions groups for default company receive connectors are anonymous users, exchange users, exchange servers, legacy exchange servers.

      For client company authetnication, the transport layer security, basic authentication, offer basic authentication after starting TLS, integrated windows authentication boxes are checked. In the permission groups tab, only the exchange userse box is checked.

      Thats all the information i can give to help out...oh, by the way, my email arrived at my gmail account while i was typing this 10 minutes after sending it...

      Comment


      • #4
        Re: Bad emails holding up and delaying Good emails

        oh yes, and forgot to mention - no black listings, no relay server issues, have SPF record, etc...also emails sent from gmail to our email server reach in a few seconds....

        Comment


        • #5
          Re: Bad emails holding up and delaying Good emails

          I do find that Google is somewhat difficult to deliver email to. Therefore it wouldn't surprise me if they are using some kind of delaying tactic as an antispam measure. When your server sends an email to a non-valid address, their servers then delay subsequent connection attempts. Nothing you can do about that. It is a war on spam and that means some people are going to get caught in the crossfire.

          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


          • #6
            Re: Bad emails holding up and delaying Good emails

            Yes, i think what you are talking about i read as greylisting which Google uses, however, i have gone and found out a few more clues:

            1. I read somewhere on a forum that the proventia intrusion prevention device has something to do with it (playing around with headers, etc). When i unplugged it from the network, all invalid emails were returned immediately and the rest of the emails went through no problem (no emails were stuck in the queue and the exchange immediately notified me that it would stop trying to send them, however, with proventia, they are stuck). So i need to check out whats up with the proventia device.

            Will keep you posted

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