Routing sync service traffic through a proxy server or firewall If you need to route Sync Service traffic to and from the hybrid service through a proxy server or firewall: Steps Under Route Sync Service Traffic, mark Route Sync Service traffic through a proxy server or firewall. Enter the IP address or hostname of the proxy server or firewall, and specify the port that is to be used. If the specified server requires authentication, enter the user name and password for Sync Service to access it. When you are finished, click OK to cache your changes. Changes are not implemented until you click Save and Deploy.