Hairpin NAT issue. #1349

New Issue

MrUnknownDE · 2026-04-05T19:08:32+02:00

MrUnknownDE commented

2026-04-05 19:08:32 +02:00

Originally created by @lthieman on 6/15/2025

Context: I have a domain name registered with Cloudflare and have a wildcard A record pointed to the public IP of a UCG Max router and ports 80, 443 and 51820 forwarded to my reverse proxy which is on a 192.168.69.xxx subnet while the rest of the house is on the 192.168.1.xxx subnet. The proxy then points to my services (audiobookshelf, etc) which are also on the 69 subnet.

Issue: This all worked perfectly without issue when I was using Nginx Proxy Manager for my reverse proxy. But I wanted to switch to Pangolin to make use of its pin code auth (I don’t need the tunneling with this setup) and everything works perfectly from the internet side but no device on the LAN side of the router can get to Pangolin or any of the services behind it. This would seem like a router issue, except it worked with Nginx Proxy Manager and I haven't been able to solve the issue with any settings in the router.

Note: I'm not using any tunneling with this setup, just a typical local reverse proxy config.

I hope this makes sense to you lovely people and you have some idea why it works with one reverse proxy and not the other. Thanks!

*Originally created by @lthieman on 6/15/2025* Context: I have a domain name registered with Cloudflare and have a wildcard A record pointed to the public IP of a UCG Max router and ports 80, 443 and 51820 forwarded to my reverse proxy which is on a 192.168.69.xxx subnet while the rest of the house is on the 192.168.1.xxx subnet. The proxy then points to my services (audiobookshelf, etc) which are also on the 69 subnet. Issue: This all worked perfectly without issue when I was using Nginx Proxy Manager for my reverse proxy. But I wanted to switch to Pangolin to make use of its pin code auth (I don’t need the tunneling with this setup) and everything works perfectly from the internet side but no device on the LAN side of the router can get to Pangolin or any of the services behind it. This would seem like a router issue, except it worked with Nginx Proxy Manager and I haven't been able to solve the issue with any settings in the router. Note: I'm not using any tunneling with this setup, just a typical local reverse proxy config. I hope this makes sense to you lovely people and you have some idea why it works with one reverse proxy and not the other. Thanks!

MrUnknownDE closed this issue

2026-04-05 19:08:32 +02:00

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Reference: github/pangolin#1349