No UDP Connection on Zyxel IPSec VPN Tunnel

[Stef085]

Hi!

I cant setup da UDP Connection from Site B to Site A (server Site) both are connected with 2 zyxel ATP-500 and IPSec VPN Tunnel.
I tuned off all firewalls, but no change.
I switched to tcp mode on Yealink phone, that works fine.

Any ideas?

thanks

Stefan

 

[Evolute IT]

Firewall rules between the two? UDP works across VPN but it's indeed usually flacky.

 

[Stef085]

I switched both firewalls off for testing... no change..
seems like the problem isn't a firewall issue

 

[NickD_3CX]

I couldn't really say what this problem is, but if you have your Yealink phones set to UDP, and from a packet capture you see UDP packets entering on Site B, and then on another packet capture on Site A they are not arriving, there is certainly something with the routing.

Also check that the VPN is transparent, meaning that from the PBX you can ping the actual IP the IP Phone has on the other end of the VPN.

 

[Stef085]

ping is fine... I dont thnik there is a different TCP routing

Thank you for helping me