Cannot use DNS with proto=tcp

mrwolf

Hi there,

I am configuring OpenVPN 2.3.2 on Ubuntu 14.04 with 2 OpenVPN instances, one listening on TCP and one on UDP.

On my Android phone I use OpenVPN for Android as client (I tried to use OpenVPN connect, but it can't import .ovpn files with embedded certificates and even splitting them into single files didn't work) and everything works correctly with the UDP instance.

When I try to use the TCP instance I cannot perform any DNS lookup. Pinging the server 10.8.1.1 works fine.

TCP configuration: http://pastebin.com/ALu2ZK8Y
UDP configuration: http://pastebin.com/0PCfucpE

I have dnsmasq running and listening on both tun0 and tun1 interfaces.

Any ideas how to troubleshoot this problem?

Traffic

mrwolf wroteWhen I try to use the TCP instance I cannot perform any DNS lookup. Pinging the server 10.8.1.1 works fine.

Your configs:

TCP: push "dhcp-option DNS 10.8.1.1"
UDP: push "dhcp-option DNS 10.8.0.1"

Did you setup a DNS server on both IP addresses ?

mrwolf

Traffic wrote
mrwolf wroteWhen I try to use the TCP instance I cannot perform any DNS lookup. Pinging the server 10.8.1.1 works fine.
Your configs:
TCP: push "dhcp-option DNS 10.8.1.1"

UDP: push "dhcp-option DNS 10.8.0.1"
Did you setup a DNS server on both IP addresses ?

Yes, as I said dnsmasq is listening on both tun0 and tun1 and I tested with an nslookup that they do work.

Traffic

How about iptables rules etc ..