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Delay on receiving of larger size of email. RRS feed

  • Question

  • Hi all,

      We are having issue with the receiving of an email with lager size. if simple text email of 7 KB or small is send from the external users, emails are getting received quickly. but when the size of an email is increased like about 400 KB or above it takes around an hour to get received those size of email from the external users.

    I have check the Firewall rules, Anti spam rules and exchange filter rules all those are been disabled. Request for your help that how can we fix such kind of issues.

    Thank you for your support.

    Monday, August 7, 2017 2:41 PM

Answers

  • Hi All,

    Thank you for your support. To figure out this issue, i have installed Network Monitor tool on CAS server and monitor the SMTP protocol. During my monitoring, i found at the time when SMTP protocol has been sniffed on CAS within few second email has been dropped.

    But still for larger email it is getting delayed to deliver, hence the next option for me was to change the ISP. and that was the right decision for me. When I changed the ISP, the email flow has been suddenly fixed. Hence it was solved by changing the ISP.

    Thank you everyone for support. :)


    Cheers, Aerrow pdhewaju.com.np Please remember to mark the replies as answers.

    • Marked as answer by AerrowMVP Tuesday, August 15, 2017 4:23 AM
    Monday, August 14, 2017 4:39 PM

All replies

  • Look at the SMTP headers of a smaller and larger message, compare them and see where the headers show the delay is taking place.  Also in the headers note the routing to be sure that both messages take the same route.  That will narrow down where you need to look.

    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."
    Celebrating 20 years of providing Exchange peer support!

    Tuesday, August 8, 2017 12:55 AM
  • Hi,

    To fix your issue, I want to confirm:
    1. How about internal mail flow with large size message?
    2. Does this issue occurs on all inbound messages, or any message from special domain?

    If this issue only occurs on inbound mail flow, I suppose that this issue is more occurs on the source side, instead of your Exchange server.

    As Ed mentioned, please open the problematic message, click File to open its properties, then copy the content in "Internet Headers" field, then use Message Header Analyzer to analyze and find the delay process. Figure as below:

    As seen, we can find the process when message delay, and then confirm whether the delay occurs on external or internal.

    Regards,

    Allen Wang


    Please remember to mark the replies as answers if they help and unmark them if they provide no help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Tuesday, August 8, 2017 2:21 AM
    Moderator
  • Hi Ed,

    I have checked the routing for both smaller and larger message and compared the headers but in both cases i have found same routing below is the snap

    this mail-flow is just of email size 400KB.


    Cheers,<br/> Aerrow<br/> <p><b>Visit:</b> <a href="http://pdhewaju.com.np" target="_blank">pdhewaju.com.np</a><br/> </p> <p>Please remember to <b>mark the replies as answers.</p> </b>

    Tuesday, August 8, 2017 4:52 AM
  • Hi Allen,

    For the internal mail-flow, there is no issues. Everything is working great for internal mail-flow. But in case of External mail we are facing problem.

    For External mail flow also there are two conditions.

    if the external sender do have same ISP for the email services as of us then no issue on mail-flow.

    But if it is different there there is issue with mail-flow. below is the header analyzer for the 400 KB email send from outlook to the internal user.

    Thank you for your support.


    Cheers,<br/> Aerrow<br/> <p><b>Visit:</b> <a href="http://pdhewaju.com.np" target="_blank">pdhewaju.com.np</a><br/> </p> <p>Please remember to <b>mark the replies as answers.</p> </b>

    Tuesday, August 8, 2017 5:00 AM
  • I can't tell anything when you obfuscate the important details, so you'll have to figure out why that hop is taking 46 minutes.

    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."
    Celebrating 20 years of providing Exchange peer support!


    Tuesday, August 8, 2017 5:58 AM
  • Hi Ed,

    Uploading the header analyzer again.


    Cheers,<br/> Aerrow<br/> <p><b>Visit:</b> <a href="http://pdhewaju.com.np" target="_blank">pdhewaju.com.np</a><br/> </p> <p>Please remember to <b>mark the replies as answers.</p> </b>

    Tuesday, August 8, 2017 3:09 PM
  • You're right, there's a delay there.  Why it is, I can't tell you.  You can turn up SMTP protocol logging on the host to maybe see more of what's going on.

    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."
    Celebrating 20 years of providing Exchange peer support!

    Thursday, August 10, 2017 12:53 AM
  • Hi,

    Do you get any useful message in protocol log?

    We need enable it on receive connector first, then reproduce it and check the log to find more details.
    Meanwhile, is there any anti-spam device between Exchange and internet?
    If so, also check the log on this device to find more information.

    Regards,

    Allen Wang


    Please remember to mark the replies as answers if they help and unmark them if they provide no help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Monday, August 14, 2017 5:56 AM
    Moderator
  • Hi All,

    Thank you for your support. To figure out this issue, i have installed Network Monitor tool on CAS server and monitor the SMTP protocol. During my monitoring, i found at the time when SMTP protocol has been sniffed on CAS within few second email has been dropped.

    But still for larger email it is getting delayed to deliver, hence the next option for me was to change the ISP. and that was the right decision for me. When I changed the ISP, the email flow has been suddenly fixed. Hence it was solved by changing the ISP.

    Thank you everyone for support. :)


    Cheers, Aerrow pdhewaju.com.np Please remember to mark the replies as answers.

    • Marked as answer by AerrowMVP Tuesday, August 15, 2017 4:23 AM
    Monday, August 14, 2017 4:39 PM
  • "

    Hi all,

      We are having issue with the receiving of an email with lager size. if simple text email of 7 KB or small is send from the external users, emails are getting received quickly. but when the size of an email is increased like about 400 KB or above it takes around an hour to get received those size of email from the external users.

    I have check the Firewall rules, Anti spam rules and exchange filter rules all those are been disabled. Request for your help that how can we fix such kind of issues.

    Thank you for your support.

    "

    what i can see the latest snap shot there is delay between two hops 

    1. 2 minutes 56 second

    2. 45 minutes 44 second

    the delay on the second hop is clearly outside of your exchange environment.

    to verify if there is any delay from your exchange server perform message tracking using the message id and then compare the time stamp and see if there is any delay in there. if you don't see the delay between the store drive submit and smtp send that means the mail went out of the exchange server without any delay.

    then the issue is not with exchange but the next hop domain.

    i hope i was able to answer your query if in case you have any questions regarding the same please let me know.

    Thanks,

    Sanjay.

    Monday, August 14, 2017 10:19 PM
  • Great, thanks for your sharing and effort.

    Regards,

    Allen Wang


    Please remember to mark the replies as answers if they help and unmark them if they provide no help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Wednesday, August 16, 2017 3:22 AM
    Moderator