If your internet service provider (ISP) engages in transparent proxying you may run into issues deploying DNSFilter. 

We've found that contacting their support can quickly update these settings, or if that's not possible setting firewall rules can bypass the proxy. 

Here are details to some known ISPs that transparent proxy DNS traffic.

Comcast

Comcast/Xfinity clients that are using static IP addresses will need to contact their ISP before installation and configuration of the DNSFilter Roaming Client. This is due to their SecurityEdge feature.

This feature set will block/reject traffic outside DNS Servers. This feature can be disabled by Comcast/Xfinity Customer Support, and it is also advised that the Modem be placed into pass-through mode. This can be accomplished by disabling the firewall features, Local IP Network DHCP, and Wi-Fi services.

T-Mobile

If you use T-Mobile's Business Internet Product, which is their primary-fixed location/ISP backup service, also comes with a transparent DNS proxy, which filters everything through OpenDNS. You will need to call T-Mobile and ask for the "Productivity Filter" to be removed from your account. This typically takes ~24 hours or less to apply to your account. 

Other ISPs may have similar practices that can be resolved by contacting their support.

Let us know about more ISPs that practice transparent proxying in the comments below!