mtg

README

mtg

Highly-opinionated (ex-bullshit-free) MTPROTO proxy for Telegram.

If you use v1.0 or upgrade broke you proxy, please read the chapter Version 2

Rationale

There are several available proxies for Telegram MTPROTO available. Here are the most notable:

• Official
• Python
• Erlang

You can use any of these. They work great and all implementations have feature parity now. This includes support of adtag, replay attack protection, domain fronting, faketls, and so on. mtg has a similar goal: to give a possibility to connect to Telegram in a restricted, censored environment. But it does it slightly differently in details that probably matter.

• Resource-efficient

  It has to be resource-efficient. It does not mean that you will see the smallest memory usage. It means that it will try to use allocated resources in zero-waste mode, reusing as much memory as possible and so on.

• Easily deployable

  I strongly believe that Telegram proxies should follow the way of ShadowSocks: promoted channels is a strange way of doing business I suppose. I think the only viable way is to have a proxy that can be restored anywhere easily.

• A single secret

  I think that multiple secrets solve no problems and just complex software. I also believe that in the case of throwout proxies, this the feature is a useless luxury.

• No adtag support

  Please read Version 2 chapter.

• No management WebUI

  This is an implementation of a simple lightweight proxy. I won't do that.

• Proxy chaining

  mtg has the support of SOCKS5 proxies. So, in theory, you can run this proxy as a frontend and route traffic via v2ray, Gost, Trojan, or any other project you like.

• Native blocklist support

  Previously, this was delegated to the FireHOL project or similar ones which track attacks and publish a list of potentially dangerous IPs. mtg has native support of such blocklists.

• Can be used as a library

  mtg v2 was redesigned in a way so it can be embedded into your software (written in Golang) with a minimum effort + you can replace some parts with those you want.

Version 2

If you use version 1.x before, you are probably noticed some major backward non-compatible details:

1. Configuration file
2. Removed support of adtag

For the configuration file, please check out the full example in this repository. It has a lot of comments and most of the options are optional. We do have only secret and bind-to sections mandatory. Other sections in the example configuration file are filled with default values.

Adtag support was removed completely. This was done to debloat mtg and keep it simple and obvious. Hopefully, this goal is achieved and the source code is clean and straightforward enough.

I always was quite skeptical about adtag. In my POV, a proxy as a fat big connectivity point for hundreds of clients is an illusion. If you work in a censored environment, the first thing that authority does is IP blocking. For us, it means, those big proxies that can benefit from having a pinned channel are going to be blocked in a minute.

Proxy has to be intimate. It has to be shared within a small group as a family or maybe your college friends. It has to have a small number of connections and never publicly announced its presence. It has to fly under the radar. If the proxy is detected, you need to be able to give a rebirth on a new IP address as soon as possible. I do no think that having some special channel for such a use case makes any sense.

But other details like replay attack protection, domain fronting, accurate FakeTLS implementation, IP blacklisting, and proxy chaining matter here. If you work in censored perimeter like GFW-protected country, you probably want to have an MTPROTO proxy as a frontend that transports traffic via cloaked tunnels made by Trojan, Shadowsocks, v2ray, or Gost. That's why you have to have the support of chaining as a first-class citizen.

Yes, this is possible and doable with optional adtag support. But the truth is that the MTPROTO proxy for Telegram is just a thing that either work as a normal client (direct mode) or doing some RPC calls in TL language (adtag support). I understand the intention of the developers and I understand that they were under high pressure fighting with RKN and doing TON after that. Nothing is ideal. But for the proxy, it means that source code is full of complex non-trivial code which is required only to support a feature that we barely need.

So, to have a reasonable MTPROTO proxy, adtag support was removed. This is a rare chance in my career where software v2 debloats a previous version. It feels so good :)

Version 1 and 2

I do continue to support both versions 1 and 2. But in a different mode.

Version 1 is now officially in maintenance mode. It means that I won't make any new features or improvements there. You can consider a feature freeze there. No bugs are going to be fixed there except for critical ones. PRs are welcome though. The goal is to keep it working. It will get some periodical updates like updates to the new Golang version of dependencies version bump, but that's mostly it.

If you want to have mtg with adtag support, please use version 1.

Version 2 is going to have all my love, active support, bug fixing, etc. It is under active development and maintenance.

This project has several main branches

1. master branch contains a bleeding edge. It may potentially have some features which will break your source code.
2. stable branch contains dumps of a master branch when we consider it 'stable'. This is a branch you probably want to pick.
3. v2 has a development of the v2.x version. In theory, it is the same as master but this will change when we have v3.x.
4. v1 has a version 1.x.

Getting started

Download a tool

Download binaries

Binaries can be downloaded from the release page. Also, you can download docker image.

For the current version, please download like

docker pull nineseconds/mtg:2

For version 1:

docker pull nineseconds/mtg:1

You may also check both Docker Hub and Github Registry. Please do not choose latest or stable if you want to avoid surprises. Always choose some version tag.

Also, if you have go installed, you can always download this tool with go get:

go install github.com/9seconds/mtg/v2@latest

Build from sources

git clone https://github.com/9seconds/mtg.git
cd mtg
make static

or for the docker image:

make docker

Generate secret

If you already have a secret in Base64 format or that, which starts with ee, you can skip this chapter. Otherwise:

$ mtg generate-secret google.com
7ibaERuTSGPH1RdztfYnN4tnb29nbGUuY29t

or

$ mtg generate-secret --hex google.com
ee473ce5d4958eb5f968c87680a23854a0676f6f676c652e636f6d

equivalent commands with docker:

$ docker run --rm nineseconds/mtg:2 generate-secret google.com
7ibaERuTSGPH1RdztfYnN4tnb29nbGUuY29t

$ docker run --rm nineseconds/mtg:2 generate-secret --hex google.com
ee473ce5d4958eb5f968c87680a23854a0676f6f676c652e636f6d

This secret is a keystone for a proxy and your password for a client. You need to keep it secured.

We recommend choosing a hostname wisely. Here we have a google.com but in reality, all providers can easily detect that this is not a Google. Google has a list of networks it officially uses and your IP address won't probably belong to it. It is a great idea to hide behind some domain that has some relation to this IP address.

For example, you've bought a VPS from Digital Ocean. Then it might be a good idea to generate a secret for digitalocean.com then.

Simple run mode

mtg supports 2 modes: simple and normal. Simple mode allows starting proxy with a small subset of configuration options you usually want to modify. This is quite good for oneliners that you can copy-paste and do not bother about external files whatsoever.

Let's take a look:

Usage: mtg simple-run <bind-to> <secret>

Run proxy without config file.

Arguments:
  <bind-to>    A host:port to bind proxy to.
  <secret>     Proxy secret.

Flags:
  -h, --help                           Show context-sensitive help.
  -v, --version                        Print version.

  -d, --debug                          Run in debug mode.
  -c, --concurrency=8192               Max number of concurrent connection to proxy.
  -b, --tcp-buffer="4KB"               Size of TCP buffer to use.
  -i, --prefer-ip="prefer-ipv6"        IP preference. By default we prefer IPv6 with fallback to IPv4.
  -p, --domain-fronting-port=443       A port to access for domain fronting.
  -n, --doh-ip=9.9.9.9                 IP address of DNS-over-HTTP to use.
  -t, --timeout=10s                    Network timeout to use
  -a, --antireplay-cache-size="1MB"    A size of anti-replay cache to use.

So, if you want to startup a proxy with CLI only, you can do something like

$ mtg simple-run -n 1.1.1.1 -t 30s -a 512kib 127.0.0.1:3128 7hBO-dCS4EBzenlKbdLFxyNnb29nbGUuY29t

The rest of the configuration will be taken from default values. But a simple run is fine if you do not have any special requirements or granular tuning. If you want it, please checkout the configuration files.

Prepare a configuration file

Please checkout an example configuration file. All options except of secret and bind-to are optional. You can safely have this minimal configuration file:

secret = "ee473ce5d4958eb5f968c87680a23854a0676f6f676c652e636f6d"
bind-to = "0.0.0.0:443"

This is enough to run the whole application. All other options already have sensible defaults for the app at almost any scale.

Oh, the configuration is done in TOML format.

Run a proxy

Put a binary and a config into your webserver. Just for example, a binary goes to /usr/local/bin/mtg and configuration to /etc/mtg.toml.

Now you can create a systemd unit:

$ cat /etc/systemd/system/mtg.service
[Unit]
Description=mtg - MTProto proxy server
Documentation=https://github.com/9seconds/mtg
After=network.target

[Service]
ExecStart=/usr/local/bin/mtg run /etc/mtg.toml
Restart=always
RestartSec=3
DynamicUser=true
AmbientCapabilities=CAP_NET_BIND_SERVICE

[Install]
WantedBy=multi-user.target
$ sudo systemctl daemon-reload
$ sudo systemctl enable mtg
$ sudo systemctl start mtg

or you can run a docker image

docker run -d -v $PWD/config.toml:config.toml -p 443:3128 --name mtg-proxy --restart=unless-stopped nineseconds/mtg:2

where 443 is a host port (a port you want to connect to from a client), and 3128 is the one you have in your config in the bind-to section.

Access a proxy

Now you can generate some useful links:

$ mtg access /etc/mtg.toml
{
  "ipv4": {
    "ip": "x.y.z.a",
    "port": 3128,
    "tg_url": "tg://proxy?...",
    "tg_qrcode": "https://api.qrserver.com/v1/create-qr-code?data...",
    "tme_url": "https://t.me/proxy?...",
    "tme_qrcode": "https://api.qrserver.com/v1/create-qr-code?data..."
  },
  "secret": {
    "hex": "...",
    "base64": "..."
  }
}

or if you are using docker:

$ docker exec mtg-proxy /mtg access /config.toml

Metrics

Out of the box, mtg works with statsd and Prometheus. Please check configuration file example to get how to set this integration up.

Here goes a list of metrics with their types but without a prefix.

Name	Type	Tags	Description
client_connections	gauge	ip_family	Count of processing client connections.
telegram_connections	gauge	telegram_ip, dc	Count of connections to Telegram servers.
domain_fronting_connections	gauge	ip_family	Count of connections to fronting domain.
iplist_size	gauge	ip_list	A size of either allowlist or blocklist in use.
telegram_traffic	counter	telegram_ip, dc, direction	Count of bytes, transmitted to/from Telegram.
domain_fronting_traffic	counter	direction	Count of bytes, transmitted to/from fronting domain.
domain_fronting	counter	–	Count of domain fronting events.
concurrency_limited	counter	–	Count of events, when client connection was rejected due to concurrency limit.
ip_blocklisted	counter	ip_list	Count of events when client connection was rejected because IP was found in the blocklist.
replay_attacks	counter	–	Count of detected replay attacks.

Tag meaning:

Name	Values	Description
ip_family	ipv4, ipv6	A version of the IP protocol.
dc		A number of the Telegram DC for a connection.
telegram_ip		IP address of the Telegram server.
direction	to_client, from_client	A direction of the traffic flow.
ip_list	allowlist, blocklist	A type of the IP list.

Documentation

Overview

mtg is just a command-line application that starts a proxy.

Application logic is how to read a config and configure mtglib.Proxy. So, probably you need to read the documentation for mtglib package first.

mtglib is a core of the application. The rest of the packages provide some default implementations for the interfaces, defined in mtglib.