I have a VPS running Ubuntu 19. The VPS is configured as follows:
- OpenVPN server on port 443
- OpenVPN has port-share with 4343
- Apache2 web server listening on 80 and 4343 (for SSL)
- OpenVPN DNS traffic passed to PiHole
- PiHole has upstream DNS set to self-hosted unbound on same VPS
This setup works. PiHole does ad blocking for VPN clients and resolves all websites properly except the one hosted on the VPS by apache at 4343. The website loads fine when not connected to the VPN. Below my iptables configuration, I believe I have loopback on so I think it should work fine. SSH works fine when connected through VPN so it seems isolated to the port sharing. The configuration was taken from PiHole documentation.
~# iptables -L
Chain INPUT (policy DROP)
target prot opt source destination
ACCEPT tcp -- anywhere anywhere tcp dpt:https
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
ACCEPT all -- anywhere anywhere
ACCEPT all -- anywhere anywhere
ACCEPT tcp -- anywhere anywhere tcp dpt:https
ACCEPT tcp -- anywhere anywhere tcp dpt:ssh
ACCEPT tcp -- anywhere anywhere tcp dpt:http
ACCEPT tcp -- anywhere anywhere tcp dpt:https
ACCEPT tcp -- anywhere anywhere tcp dpt:domain
ACCEPT udp -- anywhere anywhere udp dpt:domain
ACCEPT tcp -- anywhere anywhere tcp dpt:http
REJECT udp -- anywhere anywhere udp dpt:80 reject-with icmp-port-unreachable
REJECT tcp -- anywhere anywhere tcp dpt:https reject-with tcp-reset
REJECT udp -- anywhere anywhere udp dpt:443 reject-with icmp-port-unreachable
Chain FORWARD (policy ACCEPT)
target prot opt source destination
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
ACCEPT all -- 10.8.0.0/24 anywhere
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
ACCEPT all -- 10.8.0.0/24 anywhere
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
