goRebind : Dynamic Reverse Proxy and DNS Resolver

This project provides a combined service: a high-performance HTTP reverse proxy and an optional local DNS server. It is designed to dynamically route traffic based on the requested host and includes advanced configuration options for SSL, outbound proxying, and HTTP/2 handling.

Features

• Dynamic Routing: Maps source hostnames (e.g., example.local) to target URLs (e.g., https://www.google.com) via a simple JSON configuration file.
• Local DNS Resolver (Optional): When enabled, it responds to A record queries for configured hosts with a specified local IP address, eliminating the need to modify your local host files.
• Enhanced Proxy Stability: Includes two crucial flags (-http2=false and -no-keep-alive) to resolve common proxy errors like tls: user canceled and Unsolicited response.
• Flexible TLS Handling: Allows skipping SSL certificate verification for local or development targets.
• HTTP/2 Control: Flag to force-enable or prevent HTTP/2 negotiation based on your backend or network requirements.

---

1. Prerequisites

You need Go installed (go version 1.18+ recommended).

2. How to Build & Run

A. Clone and Build:

# Clone or ensure you are in the project directory
go build -o goRebind .

3. Run (Basic):

./goRebind
# Output: HTTP Redirector listening on port 80...

4. Run (With DNS):

# Example for Linux/macOS
./goRebind -config config.json -port 8080 -dns -I wlan0

4. Run (Custom):

./goRebind -config config.json -port 8080 

3. Example Config File

Create a file named config.json:

[
  {
    "source": "api.localhost",
    "target": "https://jsonplaceholder.typicode.com"
  },
  {
    "source": "local-app.com",
    "target": "http://127.0.0.1:9090"
  },
  {
    "source": "secure.internal",
    "target": "https://192.168.1.50"
  }
]

Command Line Flags

Flag	Type	Default	Description
-port	int	80	Port for the HTTP reverse proxy to listen on.
-config	string	(auto-detect)	Path to the JSON configuration file.
-skip-ssl-verify	bool	true	Skips TLS certificate verification for upstream targets. Useful for self-signed certificates.
-proxy	string	""	Outbound HTTP proxy URL (e.g., http://user:pass@10.0.0.1:8080).
-http2	bool	false	Force-enable HTTP/2. Set to true if your targets support H2 and you require it. (Note: Setting this to false applies stability fixes to prevent the 'tls: user canceled' error.)
DNS Flags
-dns	bool	false	Enable the local DNS server on port 53 (UDP).
-interface, -I	string	""	Network interface name (e.g., eth0 or en0). The IPv4 address of this interface will be returned for all matched hostnames. Required if -dns is enabled.
-verbose	bool	false	Enable verbose logging. Only shows DNS queries that result in a system lookup (misses).
-no-keep-alive	bool	false	Disable HTTP connection reuse (keep-alives). Use this flag if you encounter "Unsolicited response" or "readLoopPeekFailLocked" proxy errors.

FAQ

Troubleshooting: httputil: ReverseProxy read error... tls: user canceled

This error often occurs when an intermediate proxy (like Burp Suite or Zap) is used, and the underlying connection is closed prematurely by the backend.

Workaround for Burp Suite:

1. Navigate to Settings > Proxy > HTTP.

2. Go to the Match and Replace rules section.

3. Add a new rule:

   • Type: Response header

   • Match: Connection: close

   • Replace: Connection: keep-alive

Find interface name in Windows

PS c:\>netsh interface show interface

Admin State    State          Type             Interface Name
-------------------------------------------------------------------------
Enabled        Disconnected   Dedicated        Local Area Connection
Enabled        Connected      Dedicated        VMware Network Adapter VMnet1
Enabled        Connected      Dedicated        WiFi
Enabled        Disconnected   Dedicated        Ethernet