DNS over HTTP iApp

Problem this snippet solves:

DNS over HTTP is a way of resolving DNS over an encrypted HTTPS stream meaning that service providers can't intercept and modify the responses.

This iApp creates an iRule which performs resolution of DNS over HTTPS (DoH) traffic.

How to use this snippet:

1. Create a pool containing DNS resolvers
2. Install the iApp as a template iApps>Templates>Templates. Hit Import and select the iApp template
3. Create an application service iApps>Application Services>Applications. Select the DoH template, select the pool created in step 1
4. Create a virtual server listening on port 443 with tcp, http and client SSL profile. Add the iRule which was created in step 3
5. Test the deployment

Tested this on version: