We have Google apps in our company for mail delivery, our business can't pay the business version yet, however, we need to control the attachment types that employees download.

We recently switched from another hosting provider who recomended us to plug Google Apps for mail when we moved the domain, we had a firewall before which was able to prevent certain file types to be downloaded.

I know the business version has section for filtering mail (postini services). Is there a hack around my problem? Anyone ever had this problem? Thank you!


The main problem is gmail apps uses ssl connection, can this be changed ? how can i get the firewall to filter files only allowing *.doc, *.xls y *.pdf.

2 Answers 2


Depends on your firewall. If your firewall's SMTP filter is smart enough, tell it to prevent TLS connections and deny the SSL SMTP port (TCP/465). All messages will be in the clear, and presumably your firewall will be able to filter attachments. The downside of doing this is that it will no longer be able to log in to the GApps SMTP server. I don't use the service so I don't know if that is a requirement.

  • I think that Ernest is talking about filtering HTTP rather than SMTP. Allowing non-HTTPS connections to Google seems a very bad idea.
    – Adam
    Feb 17, 2011 at 9:22

Changing Google Apps to use a non-SSL connection is a bad idea, because it would allow people between your office and Google to see everything that you're doing. Of course it also prevents your firewall from seeing it, which is why it can't filter on it.

Some higher-end firewalls can do something like "HTTPS Inspection", though this would require some configuration of your client machines.

As far as I know there is no way to filter attachments on a domain-wide basis without the Postini services. But if you're relying on this for your business then I would recommend upgrading to the premium service, both for the Postini services (which have other benefits as well) and for the extra level of support.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.