Feature Request: Support for Custom Domain Names and Raw TCP/TLS Passthrough #573
Description
Issue statement
I am looking for a first-party Microsoft alternative to ngrok that supports two specific advanced networking requirements:
Custom Domains: The current persistent tunnel URLs (e.g., *.devtunnels.ms) are random. This creates friction when working with third-party webhooks, OAuth callbacks, and mobile app configurations that expect a stable, branded, or specific domain name (e.g., api.mycompany.dev).
TLS Passthrough / Raw TCP: Currently, dev tunnels seem to terminate TLS at the edge. I have a service that manages its own SSL certificates locally. I need the tunnel to act as a "Layer 4" proxy, passing the raw TCP stream to my local machine so that the local machine can handle the TLS handshake and certificate validation.
Desired solution
Custom Domains: An option to link a custom domain (via CNAME or TXT verification) to a dev tunnel, similar to ngrok's --domain flag.
Raw TCP Mode: A mode (perhaps devtunnel host -p 443 --protocol tcp) that disables HTTP-level inspection/termination and allows raw TCP packets to flow through. This is essential for non-HTTP protocols and for local TLS termination.
Support for these features would allow developers to test complex networking scenarios (like mutual TLS or raw socket communication) with the same ease as simple webhooks.