Port Usage Debacle and DNS problems
I've been struggling for a while now, and I would really appreciate some help with the following.
I want to host a pritunl VPN at location A. This single machine will run pritunl (on CentOS 8), and a collection of docker containers with services such as OwnCloud, PiHole, GitLab, ... Preferably I want the PiHole to be the DNS server for this VPN. Then I also want to connect a machine from location B to this VPN such that services on machine B are available to anyone connected to the VPN.
I run into two problems: the port usage by pritunl and DNS server configuration (i think)
The machine running pritunl at location A is in itself located in a private network. This private network has a Fritz Box that connects it to the internet. I want to forward the specific ports that Pritunl uses to this machine, but when I forward ports 80/udp+tcp, 443/udp+tcp, 1194/udp+tcp, 17593/udp to this machine any client connection (Linux Pritunl Client, IOS OpenVPN client) times out. I added ports 80 and 443 to be able to access the webpanel (which I can access both connected and not connected to the VPN), and port 1194 because this should be the port used by the OpenVPN protocol. My Pritunl server runs on port 17593. When I fully expose this machine, any client can connect no problem.
When digging into this further I also discoverd that there is a service listening on 9756/tcp, which I added, which did not help. Can anybody shed some light on this problem?
When I use my VPN (with the machine at location A fully exposed) my DNS gives me problems. Programs such as curl, ping, and mtr will completely fail to resolve any domain name (but will find ip-adresses within the VPN), and firefox will load any webpage really (REALLY) slowly. My guess is that Firefox has some kind of fail safe DNS mechanism (but I am really unsure about this). This happens with all of the following DNS servers: 22.214.171.124, 126.96.36.199, 188.8.131.52, 127.0.0.1 (pihole) and the adress of the Fritz Box. Can anybody tell me what I am doing wrong?
I am in a bit of a hurry when writing this, so I hope that my questions are clear. If there are log files or settings that I can share to improve the information for you, please let me know. Thanks in advance for any help.
Posted by Lodewijk 25 days ago