Author Topic: Mail Shield doesn't work with my email client setup  (Read 2290 times)

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Mail Shield doesn't work with my email client setup
« on: January 19, 2017, 02:49:16 PM »
I am using eM Client as an alternative to Outlook.  The client is connected to an exchange server via the Exchange Web Services and not Activesync.  I find that Avast will not detect any malicious attachments while I look at e-mail in this client.  Avast will detect the same items in Outlook(Activesync) and alternative client Zimbra(which connects to Exchange via IMAP).  So, do I need to add ports to scan in Avast Mail settings or is there some other issue?

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Re: Mail Shield doesn't work with my email client setup
« Reply #1 on: January 24, 2017, 04:54:05 AM »
I'm having a guess here :)

Exchange Web Services I expect is using port 443 (HTTPS), and as such would be managed by the Web Scanning template settings, not the Mail Shield settings.  Also, you might need to turn off "Do not scan trusted sites" which I think is enabled by default.  Being HTTPS, Avast is probably not scanning any of your mail via that protocol because of that tickbox. 

Of course to complicate matters, EWS doesn't have to use 443 as it's port, in which case Avast would have to fall back to file level scanning (ie, when an attachment is opened/saved) and you'd be out of luck trying to scan as the mail is downloaded.

Now, this doesn't really explain why Activesync is detecting.  Maybe it is using port 80 (HTTP) which is not affected by that tickbox. 

I can't predict what the side-effects of changing that tickbox setting might be.  You'd best speak to Tech Support for correct advice.

If you are not running something like Premium to do Exchange protection at the Mailbox level you might want to consider that above all else.  Much better to defend at the gateway first then at the endpoint.