Client can't re-resolve DDNS IP in broken session and reconnect

vr1152

Hello everyone!

I have OpenVPN server, now on Debian (2.4.7), before on Windows (2.5.0) (i think it doesn't matter)
And I have windows client which using OpenVPN 2.5.2 and connect to the server with DDNS hostname in "remote"

all works fine, but when the WAN public ip of the server is changed, during the connection is alive, the client start reconecting, but it doesn't re-resolve DDNS hostname again and use old IP, that was resolved when the
connection was established first time. And it goes forever, until user manually pressed "reconnect" on OpenVPN GUI, or disconnect and connect again.
After that the OpenVPN resolve DDNS, get new, correct IP and connection back alive again.

How i can ask OpenVPN re-resolv DDNS name during re-connection?

All that i can find, it,s add "--remap-usr1 SIGHUP" in client config.
But this option make unavailable "persist-tun" and make a hard restart, but as i think, i don't need it. Maybe i am wrong? Is it correct way?
Now, i made this change and i waiting that situation again to test it :)

Can anyone say something, how to solve this problem in a correct way?

I understand that the best solution would be static IP address, but anyway.

client
dev tun
proto udp
nobind
remote myDDNSname.net 1194
resolv-retry infinite
connect-retry 10 3600
tls-client
remote-cert-tls server
persist-key
persist-tun
ca ca.crt
cert cl.crt
key cl.key
tls-crypt ta.key
cipher AES-256-GCM
log-append log.txt
verb 4

TinCanTech

Yes, this is a tricky situation ..

I know it will not work but you could try adding --float to your client config file.
Edit: If you have a suitable --keepalive setting then this could work.

The problem is that openvpn must restart to re-resolve the DNS name of your server.

I think the only logical answer is to pay for a fixed server IP address.

vr1152

TinCanTech, Thanks for reply.
"--float" is interesting, i forgot about it. And yes, a have "keepalive 5 60" in config, maybe i missed this line when copied the client cfg file by parts, sorry.

The problem is that openvpn must restart to re-resolve the DNS name of your server.

I'll try also the "--remap-usr1 SIGHUP" maybe it can solve the problem.

Now i'm waiting this situation again :)

TinCanTech

I would be more interested to know if --float works.