Configuring a Firewall for Box or Box Sync



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When configuring your firewall to allow Box as a trusted source, please use the steps outlined below:

1. Use our site's domain names instead of a particular site IP address as IP addresses can change frequently and without notice. Please configure host names to recognize any sub-domain of:

  • (Details)

If you are unable to use wildcards as shown in the list above, please allow these specific hostnames:,,,,[1],,,,,,,,,,,,,,,,,, through,[2][3]

[1] is a new addition to the list above.
[2] new hostnames cdn01 – being added after May 31, 2014
[3] added June 2014

Box Sync-specific servers:

These domains are used by the Box Sync client. 


2. Enable HTTPS (port 443) and HTTP (port 80) for the domains above.

Due to the numerous firewalls available we cannot provide specific instructions for each firewall beyond what is listed above. If you are using a firewall or proxy such as Websense, Blue Coat, etc., please create a Box User Services case  and request any additional domains or custom subdomains that may be required with Enterprise accounts.


Configuring a Proxy for Box Sync

1. What client settings are supported?

  • Automatic Proxy Detection 
  • Automatic Proxy Configuration (PAC file)
  • Manual setting: Select Web Proxy (HTTP) and Secure Web Proxy (HTTPS) and enter the IP address or host name for your proxy server

2. What server settings are supported?

  • Proxy server without authentication
  • Proxy server with NTLM AD authentication

3. What are the proxy exceptions?

  • Windows: The following exceptions apply to both Sync 3 and Sync 4.
    • Box Sync for Windows does not work with NTLM V2 .
    • The Windows API does not support local file path schema (file://C:\proxy.pac).  Box Sync works if the PAC file path starts with HTTP or HTTPS, but if it doesn't work if the pac file path is the local path. 
  • Mac: Box Sync only supports manual configurations on Sync 3.

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