Server Port Mapping: Exposing LarkXR Cluster via Port Forwarding

## Overview

This guide covers configuring port mapping to expose a LarkXR cluster to the external network. It applies to scenarios where rendering servers are on a private LAN and not directly reachable from the internet, but accessible through a gateway machine that has both LAN and WAN interfaces.

**Use Case:**
- Rendering servers are on a private LAN (e.g., 192.168.0.229, .230, .231)
- A gateway machine has both LAN and WAN interfaces
- Port mapping rules forward external traffic to the internal cluster

## Prerequisites

Deploy the cluster using the intranet cluster method. Refer to [Cluster Intranet](https://docs.paraverse.cc/doc/247/). After the intranet cluster is running, configure port mapping on the gateway server as described below.

## Linux: Port Mapping with iptables

### Map Port 8181 (TCP)

```bash
#!/usr/bin/bash
remote_ip=192.168.31.253
remote_port=8181
local_port=80
P=tcp
iptables -t nat -A PREROUTING -p $P --dport ${local_port} -j DNAT --to-destination ${remote_ip}:$remote_port
iptables -A FORWARD -p $P -d $remote_ip --dport $remote_port -j ACCEPT
iptables -t nat -A POSTROUTING -d $remote_ip -j MASQUERADE
```

### Map Port 8182 (TCP)

```bash
#!/usr/bin/bash
remote_ip=192.168.31.253
remote_port=8182
local_port=8182
P=tcp
iptables -t nat -A PREROUTING -p $P --dport ${local_port} -j DNAT --to-destination ${remote_ip}:$remote_port
iptables -A FORWARD -p $P -d $remote_ip --dport $remote_port -j ACCEPT
iptables -t nat -A POSTROUTING -d $remote_ip -j MASQUERADE
```

### Map UDP Port Range 10011-10050 (Batch)

Use a shell script to batch-configure UDP port forwarding for multiple rendering nodes:

```bash
#!/usr/bin/bash

# Render Node 1 (ports 10011-10030)
remote_ip=192.168.31.253
for i in {10011..10030}; do
  iptables -t nat -A PREROUTING -p udp --dport $i -j DNAT --to-destination ${remote_ip}:$i
  iptables -A FORWARD -p udp -d ${remote_ip} --dport $i -j ACCEPT
  iptables -t nat -A POSTROUTING -d ${remote_ip} -j MASQUERADE
done

# Render Node 2 (ports 10031-10050)
remote_ip=192.168.31.11
for i in {10031..10050}; do
  iptables -t nat -A PREROUTING -p udp --dport $i -j DNAT --to-destination ${remote_ip}:$i
  iptables -A FORWARD -p udp -d ${remote_ip} --dport $i -j ACCEPT
  iptables -t nat -A POSTROUTING -d ${remote_ip} -j MASQUERADE
done
```

## Windows: Port Mapping with netsh

### Map Port 8181 (TCP)

1. Open a Command Prompt as Administrator.
2. Run the following command to add a port mapping for port 8181:

```cmd
netsh interface portproxy add v4tov4 listenport=8181 listenaddress=0.0.0.0 connectport=8181 connectaddress=192.168.31.253
```