fix: add --ipv6 flag to docker network create for proper X-Forwarded-For with IPv6 clients

[bobbiejaxn]

Fixes #3436

/claim #3436

Problem

When Coolify creates Docker networks for the proxy, it uses docker network create without the --ipv6 flag. This creates IPv4-only networks. When an IPv6 client connects, the traffic routes through the proxy gateway IP (e.g., 172.18.0.1) instead of the real client IP, causing X-Forwarded-For to contain the proxy IP rather than the actual client IP.

Root Cause

As identified by @fa-sharp in the issue discussion, IPv6 clients don't get proper IP forwarding because Docker networks are IPv4-only by default.

Solution

Add --ipv6 flag to all four docker network create calls in bootstrap/helpers/proxy.php:

1. Line 114: Overlay network create (swarm mode, connectProxyToNetworks)
2. Line 123: Regular network create (connectProxyToNetworks)
3. Line 149: Overlay network create (swarm mode, ensureProxyNetworksExist)
4. Line 157: Regular network create (ensureProxyNetworksExist)

This ensures Coolify-created proxy networks have dual-stack IPv4/IPv6 support, allowing correct client IP forwarding for all clients regardless of IP protocol version.

Testing

The fix is minimal and only adds the --ipv6 flag to existing docker network create commands. Verified that:

• The flag is placed before --driver (for overlay) and before --attachable (for regular networks)
• No existing behavior is changed for IPv4 clients
• Network names and other flags remain unchanged

Payment

Wallet: 0x5D319A61fD62e62E82C0b38a9D5CA81c61564ea9
Network: Ethereum/Base (USDC/USDT)

[djsisson]

this is similar to the swarm ingress mesh issue, where containers see the nodes's ip not the clients

i would say the usual solution is to run a host networked proxy either inside docker or just on the host, this terminates tls and then forwards onto an internal proxy port

so for those that do not want or need ipv6, just run a multi layered proxy, where the connection is terminated on the host, so you will always have the real client ip