Skip to content

Protocol Shorts: MITM Proxies and Transparent L4 Interception

March 17, 2026 · 16 min

Show notes

episode 31 — Protocol Shorts: MITM Proxies and Transparent L4 Interception.

In this second "Protocol Shorts" episode, we look at man-in-the-middle proxies from the transport layer up. The episode explains how HTTP proxies, HTTP CONNECT, and SOCKS5 differ, why they all assume a proxy-aware client, and what changes when a transparent layer 4 proxy is inserted by the operating system instead.

From there, we dig into protocol detection from the first bytes on the wire and into the BridgeIo abstraction in Rama: a way to relay and inspect stacked handshakes incrementally instead of terminating every protocol upfront.

Learn more:

Rama

If you like this podcast you might also like our modular network framework in Rust: https://ramaproxy.org

Chapters

  • 00:00 Intro
  • 01:00 Understanding Proxies: The Basics
  • 01:18 Diving Deeper into Proxy Types
  • 04:16 Layer 4 Proxies: A New Approach
  • 05:23 Challenges of Transparent Proxies
  • 07:53 Bridging Conversations: A New Insight
  • 09:53 Example: HTTPS request within a SOCKS5 tunnel
  • 13:41 Layer 4 Proxies and Protocol Reconstruction
  • 15:15 Outro

Netstack.FM

Music for this episode was composed by Dj Mailbox. Listen to his music at https://on.soundcloud.com/4MRyPSNj8FZoVGpytj

All episodes of netstack.fm

Settings

Display

Language

Decides which stations you see first on the home page.

History

Recently played stations and episodes and your latest searches are only stored in this browser.

Notifications

A short notice when a podcast you follow has a new episode. Turn off single podcasts with the bell on their page.

Account

Save favorites – in the app and on the website.

Keyboard shortcuts

/
Open search
Space
Play or pause
← →
In the player: back 15 s, forward 30 s (episodes) · in a row: next tile
↑ ↓
In a row: target within the tile
Home / End
In a row: first or last tile
Esc
Close window or menu
?
This overview
Now playing

Go to station page

Play next

    Add episodes with “Play next” – they play after the current episode.