>From the tinc log I can see: the client side(behind the firewall) neverreceive the MTU probe from server side(public IP), so my question is what is the packet looks like for the MTU probe packet? It's a UDP packet? Source/destination of UDP port is the tinc host configuration? And why firewall blocked this? How to adjust to make it more friendly? -- Sent from iPhone -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://www.tinc-vpn.org/pipermail/tinc/attachments/20170718/710b9b39/attachment.html>