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+++ b/mod_net_proxy/README.markdown	Thu Mar 15 15:26:30 2018 +0100
@@ -0,0 +1,153 @@
+---
+labels:
+- 'Stage-Alpha'
+summary: 'Implementation of PROXY protocol versions 1 and 2'
+...
+
+Introduction
+============
+
+This module implements the PROXY protocol in versions 1 and 2, which fulfills
+the following usecase as described within the official protocol specifications:
+
+> Relaying TCP connections through proxies generally involves a loss of the
+> original TCP connection parameters such as source and destination addresses,
+> ports, and so on.
+> 
+> The PROXY protocol's goal is to fill the server's internal structures with the
+> information collected by the proxy that the server would have been able to get
+> by itself if the client was connecting directly to the server instead of via a
+> proxy.
+
+You can find more information about the PROXY protocol on
+[the official website](https://www.haproxy.com/blog/haproxy/proxy-protocol/)
+or within
+[the official protocol specifications.](https://www.haproxy.org/download/1.8/doc/proxy-protocol.txt)
+
+
+Usage
+=====
+
+Copy the plugin into your prosody's modules directory. And add it
+between your enabled modules into the global section (modules\_enabled).
+
+As the PROXY protocol specifications do not allow guessing if the PROXY protocol
+shall be used or not, you need to configure separate ports for all the services
+that should be exposed with PROXY protocol support:
+
+```lua
+proxy_ports = {15222, 15269}
+proxy_port_mappings = {
+	[15222] = "c2s",
+	[15269] = "s2s"
+}
+```
+
+The above example configuration, which needs to be placed in the global section,
+would listen on both tcp/15222 and tcp/15269. All incoming connections to these ports
+have to be initiated by a PROXYv1 or PROXYv2 sender and will get mapped to the
+configured service name after initializating the connection.
+
+Please note that each port handled by _mod_net_proxy_ must be mapped to another
+service name by adding an item to _proxy_port_mappings_, otherwise a warning will
+be printed during module initialization and all incoming connections to unmapped ports
+will be dropped after processing the PROXY protocol requests.
+
+The service name can be found by analyzing the source of the module, as it is the
+same name as specified within the _name_ attribute when calling
+`module:provides("net", ...)` to initialize a network listener. The following table
+shows the names for the most commonly used Prosody modules:
+
+  ------------- --------------------------
+  **Module**    **Service Name**
+  c2s           c2s (Plain/StartTLS)
+  s2s           s2s (Plain/StartTLS)
+  proxy65       proxy65 (Plain)
+  http          http (Plain)
+  net_multiplex multiplex (Plain/StartTLS)
+  ------------- --------------------------
+
+This module should work with all services that are providing ports which either
+offer plaintext or StartTLS-based encryption. Please note that instead of using
+this module for HTTP-based services (BOSH/WebSocket) it might be worth resorting
+to use proxy which is able to process HTTP and insert a _X-Forwarded-For_ header
+instead.
+
+
+Example
+=======
+
+This example provides you with a Prosody server that accepts regular connections on
+tcp/5222 (C2S) and tcp/5269 (S2S) while also offering dedicated PROXY protocol ports
+for both modules, configured as tcp/15222 (C2S) and tcp/15269 (S2S):
+
+```lua
+c2s_ports = {5222}
+s2s_ports = {5269}
+proxy_ports = {15222, 15269}
+proxy_port_mappings = {
+	[15222] = "c2s",
+	[15269] = "s2s"
+}
+```
+
+After adjusting the global configuration of your Prosody server accordingly, you can
+configure your desired sender accordingly. Below is an example for a working HAProxy
+configuration which will listen on the default XMPP ports (5222+5269) and connect to
+your XMPP backend running on 192.168.10.10 using the PROXYv2 protocol:
+
+```
+defaults d-xmpp
+	mode tcp
+	option redispatch
+	option tcplog
+	option tcpka
+	option clitcpka
+	option srvtcpka
+	
+	timeout connect 5s
+	timeout client 24h
+	timeout server 60m
+
+frontend f-xmpp
+	bind :5222,:5269	
+	use_backend b-xmpp-c2s if { dst_port eq 5222 }
+	use_backend b-xmpp-s2s if { dst_port eq 5269 }
+	
+backend b-xmpp-c2s
+	balance roundrobin
+	option independant-streams
+	server mycoolprosodybox 192.168.10.10:15222 send-proxy-v2
+	
+backend b-xmpp-s2s
+	balance roundrobin
+	option independant-streams
+	server mycoolprosodybox 192.168.10.10:15269 send-proxy-v2
+```
+
+
+Limitations
+===========
+
+It is currently not possible to use this module for offering PROXY protocol support
+on SSL/TLS ports, which will automatically initiate a SSL handshake. This might be
+possible in the future, but it currently does not look like this could easily be
+implemented due to the current handling of such connections.
+
+
+Important Notes
+===============
+
+Please do not expose any ports offering PROXY protocol to the internet - while regular
+clients will be unable to use them anyways, it is outright dangerous and allows anyone
+to spoof the actual IP address. It is highly recommended to only allow PROXY
+connections from trusted sources, e.g. your loadbalancer.
+
+
+Compatibility
+=============
+
+  ----- -----
+  trunk Works
+  0.10  Works
+  ----- -----