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Sophos XG high traffic on the BITS application

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Symptom

The Windows and Office 2016 updates use the operating system BITS to download the updates.

The passage in the proxy of the firewall and the antivirus scan “prevents” the download and it runs in a loop saturating the tape..

You can see on the screenshot below the statistics on 12 hours with almost 80GB of download.
Statistiques internet

How you can see them also on the following screenshots made with PRTG on the monitoring of firewall interfaces, only the Wan interface (left) is impacted, the Lan interface (right) of the firewall records normal traffic. All download data do not go to the post on your network.
Port WAN port lan

Resolution

To solve this problem, you must add a proxy control exception to do a bypass on the antivirus scan

1. From the interface of your firewall, go to Web 1 > Exceptions 2 and click on the pencil 3 to edit the exception Microsoft Windows Update.
Sophos XG Web > Exceptions

2. Edit the exception by adding the following domains 1 and click on Save 2.
sophos xg exception windows update

officecdn.microsoft.com.edgekey.net
officecdn.microsoft.com.edgesuite.net
officecdn.microsoft.com

3. Enable the exception by moving the cursor to ON 1 if this is not already the case.
Activer exception

4. Wait a little while the rule applies and the data is sent to the post. How you can see on the catch below the traffic is back to normal 1.
Trafic de retour à la normale

For further

I take this article also to introduce another exception, which is that of url url deploy.static.akamaitechnologies.com. Microsoft also uses this service to offer updates.

1. From the exceptions page, click on the button .

2. Give a name 1, check the box URL template matches 2, enter the regex 3 below, check the boxes 4 to ignore the checks and click on Save 5.
Ajout exception

^([A-Za-z0-9.-]*\.)?deploy\.static\.akamaitechnologies\.com/

3. Your exception has been added 1, move the cursor to ON 2 to activate it.
Sophos XG exception ajoutée

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