Why am I unable to access Dropbox™?

Article #: Product Castle
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How to allow Dropbox with Smoothwall.


You are unable to access Dropbox.

Dropbox does not support SNI and therefore does not work through a Transparent HTTPS Proxy.

When installing, the Dropbox installer does not perform consistently with proxies.


Firewall Configuration

You need to ensure direct access outbound on port 443 is allowed temporarily. This can be done via port rule configuration. Allow the following network ports for these IP addresses:

Network Ports:

  • HTTP = TCP 80
  • HTTPS = TCP 443

IP Networks used by the Dropbox service:


For a detailed description of how to create firewall rules on the Smoothwall, see https://help.smoothwall.net/Latest/Content/ui/admin/ipfilter/forward.htm.

Guardian Configuration

  1. As Dropbox doesn't support NTLM, add an authentication exception for dropbox.com — see https://help.smoothwall.net/Latest/Content/modules/guardian3/cgi-bin/guardian/authexceptions.htm
  2. Tip: It is best to terminate the program, set up your Authentication exception, and restart the program. If you are using SSL Login, this should not be a problem although you need to ensure that your users have logged in to authenticate their browsing session.

  3. Create an Allow web filter policy for the Dropbox domains listed in this article — https://www.dropbox.com/en/help/217.
  4. Move this policy above any file and image hosting block policies you may have in the Web filter policies table, as Dropbox is part of these categories.

Dropbox Application Configuration

You need to set your proxy settings manually in the application by right clicking on the Dropbox icon on the top right task bar once installed.

Note: If you are using Dropbox for PC and the proxy connection fails, the application reverts to using a direct connection.


Last updated: Author: Contributions by:
06 September 2016   Tanja