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Akilan-website/content/technicalposts/P2PRC-Escaping-NAT.md
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---
title: "Draft for escaping NAT with reverse proxy P2PRC"
summary: Annoying NAT boo boo
date: 2021-10-11
aliases: ["/P2PRC-escaping-NAT"]
tags: ["P2PRC","NAT"]
author: "Akilan Selvacoumar"
draft: false
aliases: [/P2PRC-escaping-NAT]
weight: 2
---
## Abstract
We focus here on escaping NAT for the project P2PRC. The intial
plan is to use a middle server with an IPV4 address to escape NAT.
The future plan would be to use a WebRTC approach to where we
use a middle server to intansiate a direct p2p connection
using UDP sockets with nodes behind NAT.
## Architecture plan
The server behind NAT would use a reverse proxy server with an IPV4 address
to be a possible way to communicate with the outside world.
Ex:
```
NAT
|
Server <--> Reverse Proxy server with <--> Clients
| public IPV4
```
We use the libaray known as [frp](https://github.com/fatedier/frp).
"frp is A fast reverse proxy to help you expose a local server behind a NAT
or firewall to the internet."
The server behind the NAT IPTable would be broadcasted through the reverse proxy.
The mapping would be done automatically though P2PRC because the reverse proxy
could have certain ports already taken.
We are introducting a new concept of detecting reverse proxies over P2PRC.
We call this ``` reverse_proxy_server.json ``` and ``` reverse_proxy_mapping.json```.
The ```reverse_proxy_server.json``` file is incharge of detecting all reverse
proxy servers and the ```reverse_proxy_mapping.json``` is incharge of logging
all the reverse proxy server mappings talking place.
#### reverse_proxy_server.json
```
{
"reverse_proxy_servers": [
{
"Server_name": <server name>,
"Address": <remote address>,
"Latency": <latency>
}, ... n
]
}
```
#### reverse_proxy_mapping.json
```
{
"reverse_proxy_mappings": [
{
"Server_name": <server name>,
"Address": <remote address>,
"Type": <TCP or UDP>,
"blind_port": <port no>
}, ... n
]
}
```
### Port allocation
The function for port allocation would need certain
modifications need to ensure that the port is not only free
on the server but also on the on reverse proxy server.
We are debate on this would occur as it requires
further reading on the inner depths of [frp](https://github.com/fatedier/frp).
The idea scenario would be that the odds a 5 or 6 digit
taken is a low probability.
### How would the ip tables would look
There would not be much change when a client looks
at it. This only difference is that the client
see's the address of the proxy server.
Ex:
```
{
"ip_address": [
{
"ipv4": "<reverse proxy address>",
"ipv6": "",
"latency": 0,
"download": 0,
"upload": 0,
"serverport": "<server port no>"
}
]
}
```
If the server is using a reverse proxy then the server
port no should be decided by P2PRC to ensure that there
is no scenario where the port is already taken.
## New Cli Commands
We will be introducing a new set of Cli commands.
These cli commands would be incharge to starting
the reverse proxy or connecting to the reverse proxy
and various other function.
1. start reverse proxy (need public IPV4)
```
p2prc -s --reverse-proxy
```
This will start the reverse
and autoamtically broadcast
as a reverse proxy as well.
2. connecting to a reverse proxy
```
p2prc -s --connect-reverse-proxy <proxy ip address>
```
This will start p2prc as server
and automatically set the server port
and link it to the reverse proxy and
any connections would go through the
reverse proxy.
3. Listing all proxy servers avaliable
```
p2prc --view-rps or p2prc --view-reverse-proxy-servers
```
4. Listing all reverse proxy connection mapping
```
p2prc --view-rpm or p2prc --view-reverse-proxy-mapping
```