OK - several changes made since I last used ZT (haven’t been on a work trip for months).
OS - upgraded to new version of Linux Mint 22. One laptop Mint 22.0 (on local network) using official ZT client. The Mint 22.1 laptop using snap client.
Home Router - upgraded to GLiNet device. Set up according to ZeroTier - GL.iNet Router Docs 4
Cell Provider - changed from one provider to another. Still have hotspot capabilities.
The Issue
RELAYS. Unfortunately my laptops are connecting via relays, whether attached to the local network, or hotspotting via the cell phone.
The Mint 22 laptop, running ZT 1.14.2 on the LAN reports “Currently connecting through a TCP relay. Ensure UDP is not blocked”.
The Mint 22.1 laptop running ZT 1.10.2 does not report this when running zerotier-cli peers. However it is connecting via relays.
Because so many things have changed on the network since I last access via ZT, I’m not sure where to begin.
UFW is disabled on both laptops.
Solution
On the GL iNET router NAT page, I enabled Full Cone NAT. This seems to have solved the problem. Devices are now connecting directly to each other.
I guess I’ll see if there is a way to enable UDP without having to enable Full Cone NAT on the GL inet router.