socks5-killswitch

Blocks all requests if your SOCKS5 proxy fails — no silent fallback.

---

SOCKS5 proxy session for Python built on requests.Session.
If the proxy drops — all requests are instantly killed. No silent fallback to your real IP.

The Problem

Standard requests + SOCKS5 proxy setup has a fatal flaw: if the proxy goes down, requests silently fall back to your real IP. You're exposed and don't even know it.

The Solution

              Request ──► Proxy OK? ──► Yes ──► Send through proxy
                              │
                              No
                              │
                         KILL SWITCH ON
                              │
                    ┌─────────┴─────────┐
                    │  All requests      │
                    │  blocked forever   │
                    │  ProxyError raised │
                    └───────────────────┘

Install

pip install socks5-killswitch

Quick Start

from socks5_killswitch import create_session, ProxyError

# Create a protected session — real IP is detected and verified automatically
session = create_session(
    host="proxy.example.com",
    port=1080,
    username="your-socks5-user",
    password="your-socks5-pass",
)

# All requests go through the proxy — just like normal requests.Session
resp = session.get("https://example.com")

# Periodic leak check — verifies visible IP != real IP
session.check_ip()

# If proxy ever fails:
# ❌ ProxyError raised
# ❌ ALL further requests blocked
# ❌ No fallback to direct connection
# ✅ Your real IP is not exposed through this session

How It Works

Event	What happens
create_session()	Detects real IP via ipify.org, connects through proxy, verifies proxy IP is different
Successful request	Passes through proxy as normal
Any request failure	Kill switch activates — _killed = True, ProxyError raised
Subsequent requests	Instantly raise ProxyError — zero network calls
check_ip()	Preflight TCP check → verifies visible IP != real IP (works even after kill switch!)

API

create_session(host, port, username, password, **kwargs)

Factory that returns a verified SafeSession.

Parameter	Type	Default	Description
host	str	—	SOCKS5 proxy host
port	int	—	SOCKS5 proxy port
username	str	—	SOCKS5 username
password	str	—	SOCKS5 password
timeout	int	15	Default request timeout (seconds)
ip_check_url	str	https://api.ipify.org	IP detection service URL
preflight	bool	True	TCP-check proxy reachability before IP verification

SafeSession

Extends requests.Session with kill switch protection.

session.get(url)              # proxied request, kills on failure
session.post(url, data=b"…")  # binary data works (AMF2, protobuf, etc.)
session.check_ip()            # returns proxy IP or raises ProxyError
repr(session)                 # <SafeSession proxy=socks5://user:***@host:1080 killed=False>

ProxyError

Raised when proxy fails or IP leak is detected. Original exception is chained via __cause__.

Security Model

What the kill switch covers

• Proxy failure → instant block — if any request through the proxy raises an exception, the session is permanently locked. No fallback to a direct connection, ever.
• IP verification on startup — create_session() detects your real IP, connects through the proxy, and confirms the proxy IP is different before returning the session.
• On-demand leak detection — check_ip() verifies your visible IP hasn't changed. Call it periodically in long-running sessions.

What is outside the scope

This is application-level protection for a single requests.Session. It does not cover:

• DNS queries — uses socks5:// by default (local DNS resolution). Your ISP can see which domains you visit. See #1.
• Requests outside SafeSession — a plain requests.get() elsewhere in your code goes direct.
• Non-HTTP traffic — WebSocket, UDP, raw sockets are not routed through the proxy.
• OS-level enforcement — other processes and applications are not affected.

For maximum protection, combine this library with a VPN or firewall rules that block non-proxied outbound traffic.

Design Decisions

• socks5:// not socks5h:// — DNS is resolved locally (required for PIA and similar providers)
• Pure library — no .env, no config files, no side effects. All parameters passed explicitly
• check_ip() bypasses kill switch — intentional; leak detection must work even in degraded state
• Preflight TCP check — check_ip() verifies proxy is TCP-reachable before hitting ipify, preventing real IP leak to external services
• Password masked in repr() — socks5://user:***@host:1080, safe for logging

License

MIT