Duplicated Emails - Outlook 2003

keat63

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Nov 20, 2014
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Over night, we generally recieve about 100 emails to our main pop3 mailbox, as well as a handful to a dozen other pop and imap mailboxes.

Every morning at 8am, people log in and start to download thier emails, I will also connect to webmail and check the server logs. I guess you could say that 8am is quite busy for half an hour.

The main pop3 mailbox will download emails, but then start to duplicate them. As if the mail server didn't recieve the instruction that the mail has been downloaded.

Could the load be causing this ?
Load on the mail server or maybe load on the internet connection out of the office ?
Can anyone suggest how I might set about trying to determine what could be causing this or impliment a solution.
 

keat63

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I'm wondering if this might related to our internal firewall doing virus checks on incoming mail.
Thinking about it, I've only had reports of this happening in the last few days, and about a week ago, there was a firewall update which addressed an antivirus issue.
Maybe this is causing a bottleneck/timeout.

Any thoughts would be appreciated.
 

cPanelMichael

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Apr 11, 2011
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I'm wondering if this might related to our internal firewall doing virus checks on incoming mail.
Thinking about it, I've only had reports of this happening in the last few days, and about a week ago, there was a firewall update which addressed an antivirus issue.
Maybe this is causing a bottleneck/timeout.
Hello,

Does the issue continue when temporarily disabling those virus checks?

Thank you.
 

ssfred

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Hello

Firewalls and Anti-virus scanners can interfere with the mail clients communications with the mail server and may leave an improperly synchronized or outdated list of downloaded mails in the mail client. This will force the client to re download the mails once again. If the mail clients are configured with reduced mail check interval, there will be too many connections and the server firewall may block or create communication issues if it is configured with strict rules. As mentioned by cPanelMichael, do check the issue after disabling the firewall/Virus scanner.

You may also refer the following KB as well https://support.microsoft.com/en-in/kb/2685726
 

keat63

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The firewall was configured to scan the fist 2048 bytes, i dropped this to 1024, and since then, i've had no reports of any errors.
I'm assuming that while the firewall was scanning the email, there was no notification back to the server that a successful transaction had occured, resulting in a subsequent retry.
 

cPanelMichael

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I'm happy to see you were able to address the issue. Thank you for updating us with the outcome.