No internet connection with OpenVPN UDP

[IsmaelZ]

Good afternoon,

I currently use Asuswrt Merlin fw 376.47 on my Asus RT-N66u router with two configurations, one for broad support (TCP 443) and one for better performance where I might be able to get it (UDP 123, 53.. etc) on school/airport/public networks

The TCP server works without a hitch, I have LAN and Internet access with internet traffic and DNS lookups being done through the VPN (see attached file)

The UDP server has the exact same settings, I only changed the protocol and the port number, obviously.. but it still doesn't work - client connects to openvpn/router but has no network and internet access.

What can I do to make this work? Is this a known issue?

Regards,
Ismael

 

[RMerlin]

Check your System Log for any error message.

 

[IsmaelZ]

I just checked my TCP vs NTP server logs and they look identical except for the TCP connection establishment and connection reset messages.

ِCould it be that certain ISPs are limiting and blocking NTP/DNS traffic upstream due to the recent DDoS attacks? Thank you for your time anyway, Merlin

 

[RMerlin]

I just checked my TCP vs NTP server logs and they look identical except for the TCP connection establishment and connection reset messages.

ِCould it be that certain ISPs are limiting and blocking NTP/DNS traffic upstream due to the recent DDoS attacks? Thank you for your time anyway, Merlin

It's possible that they block inbound connection to known service ports, as they want to ensure that their (home) customers don't host their own servers. Port 25 is almost unversally blocked inbound. I suspect a few might also block 80, 443, 53, etc...

There's also a good chance that port 53 would conflict with dnsmasq.