On 7/5/24 11:31, Ronald Klop wrote:
Of course this can be a firewall or routing issue somewhere in between
the hosts blocking traffic from B to A.
Hmm...
The two hosts can communicate with any other protocol.
Also the VPN can handshake, so packets are exchanged correctly.
I'm only using ipfw: no packet is logged as blocked, but, in any case,
it blocks after tcpdumps sees them and I don't even see them.
> Or both? Can you run tcpdump on the physical interfaces? What
> traffic do you see on the openvpn port?
Let's say, after handshake, I ping A -> B:
_ A sees the request going out tun;
_ A sees the UDP packet going out via physical interface;
_ B sees the UDP packet arriving;
_ B sees the request coming in via tun;
_ B sees the answer going out via tun;
_ B sees the UDP packet going out the physical interface;
_ A doesn't see the UDP packet coming in (so obviously nothing on tun also).
Can you switch to TCP?
Would be a little work and using OpenVPN/TCP is highly discouraged.
However, I just changed UDP port and it seems to work!
I'm puzzled...
So maybe some system in between my two hosts was blocking packets,
but... after the handshake!?!?!?
Very strange.
Or host B has some trouble and changing its port helped???
In any case, thanks a lot for answering.
bye
av.
