A transparent TCP to SOCKSv5/HTTP proxy on Linux written in Rust.

Features:

• Transparent TCP proxy with iptables -j REDIRECT or nft redirect to
• Downstream SOCKSv5 as a supplement to transparent proxy
• Multiple SOCKSv5/HTTP upstream proxy servers
• SOCKS/HTTP-layer alive & latency probe for upstreams
• Prioritize upstreams according to connection quality (latency & error rate)
• Full IPv6 support
• Proxy selection policy (see conf/policy.rules)
• Multiple downstream listen ports (for proxy selection policy)
• Remote DNS resolving for TLS with SNI (extract domain name from TLS handshaking)
• Optional try-in-parallel for TLS (try multiple proxies and choose the one first response)
• Optional status web page (latency, traffic, etc. w/ curl-friendly output)
• Optional Graphite and OpenMetrics (Prometheus) support (to build fancy dashboard with Grafana for example)
• Customizable proxy selection algorithm with Lua script (see conf/simple_scroe.lua).

+-----+  TCP  +-----------+       SOCKSv5   +---------+
| App |------>| firewall  |    +----------->| Proxy 1 |--->
+-----+       +-----------+    |            +---------+
            redirect |         |
+-----+           to v         |      HTTP  +---------+
| App |       //=========\\    |   +------->| Proxy 2 |--->
+-----+       ||         ||----+   |        +---------+
   |          || MOPROXY ||--------+             :
   +--------->||         ||-----------···        :
   SOCKSv5    \\=========//  Selection  |   +---------+
                          |  policy     +-->| Proxy N |--->
                          |                 +---------+
                          |
                          +----------- Direct ------------>

There are CLI and/or configure changes among:

• v0.4 => v0.5
• v0.3 => v0.4

See MIGRATION.md

moproxy --help

Assume there are three SOCKSv5 servers on localhost:2001, localhost:2002, and localhost:2003, and two HTTP proxy servers listen on localhost:3128 and 192.0.2.0:3128. Following commands forward all TCP connections that connect to 80 and 443 to these proxy servers.

moproxy --port 2080 --socks5 2001 2002 2003 --http 3128 192.0.2.0:3128

# redirect local-initiated connections
nft add rule nat output tcp dport {80, 443} redirect to 2080
# redirect connections initiated by other hosts (if you are router)
nft add rule nat prerouting tcp dport {80, 443} redirect to 2080

# or the legacy iptables equivalent
iptables -t nat -A OUTPUT -p tcp -m multiport --dports 80,443 -j REDIRECT --to-port 2080
iptables -t nat -A PREROUTING -p tcp -m multiport --dports 80,443 -j REDIRECT --to-port 2080

SOCKSv5 server is also launched alongs with transparent proxy on the same port:

http_proxy=socks5h://localhost:2080 curl ifconfig.co

Put upstream proxies on a file to avoid messy CLI arguments and enable features like priority (score base), username/password auth, capabilities, etc.

See proxy.ini example for details.

Pass file path to moproxy via --list argument.

Signal SIGHUP will trigger the program to reload the list.

Let specified connections use only a subset of upstream proxies.

See policy.rules example for details.

Pass file path to moproxy via --policy argument.

Signal SIGHUP will trigger the program to reload the list.

Proxy servers are sorted by their score, which is re-calculated after each round of alive/latency probing. Server with lower score is prioritized.

The current scoring algorithm is a kind of weighted moving average of latency with penalty for recent connection errors. This can be replaced with your own algorithm written in Lua. See conf/simple_score.lua for details.

Source/destination address–based proxy selection is not directly supported. One workaround is let moproxy bind multiple ports, delegates each port to different proxy servers with listen ports in your config, then doing address-based selection on your firewall.

Metrics (latency, traffic, number of connections, etc.) are useful for diagnosis and customing your own proxy selection. You can access these metrics with various methods, from a simple web page, curl, to specialized tools like Graphite or Prometheus.

--stats-bind [::1]:8080 turns on the internal stats page, via HTTP, on the given IP address and port number. It returns a HTML page for web browser, or a ASCII table for curl.

The stats page only provides current metrics and a few aggregations. Graphite (via --graphite) or OpenMetrics (via --stats-bind then \metrics) should be used if you want a full history.

Some examples of Prometheus query (Grafana variant):

Inbound bandwith:
rate(moproxy_proxy_server_bytes_rx_total[$__range])

Total outbound traffic:
sum(increase(moproxy_proxy_server_bytes_tx_total[$__range]))

No. of connection errors per minute:
sum(increase(moproxy_proxy_server_connections_error[1m]))

Average delay for each proxy server:
avg_over_time(moproxy_proxy_server_dns_delay_seconds[$__interval])

Sample service file: conf/moproxy.service

Implemented features:

• Watchdog
• Reloading (via SIGHUP signal)
• Notify (type=notify, reloading, status string)

Get simple status without turing on the HTTP stats page:

$ systemctl status moproxy
> ...
> Status: "serving (7/11 upstream proxies up)"
> ...

You may download the binary executable file on releases page.

Arch Linux user can install it from AUR/moproxy.

Or compile it manually:

# Install Rust
curl https://sh.rustup.rs -sSf | sh

# Clone source code
git clone https://github.com/sorz/moproxy
cd moproxy

# Build
cargo build --release
target/release/moproxy --help

# If you are in Debian
cargo install cargo-deb
cargo deb
sudo dpkg -i target/debian/*.deb
moproxy --help

Refer to conf/ for config & systemd service files.