On this version I’m not getting any ARP responses from other routers within my Zerotier network. Downgrade to 7.16.2, same config works again. I also tried 7.18beta6, have the same problem. Full details of my issue, including the most minimal test config possible, are here: http://forum.mikrotik.com/t/zerotier-struggles-on-v7-17/181819/4
EDIT: The issue for me specifically appears to be related to this part of my Flow Rules, which was from a default example provided by Zerotier:
tag server
id 2
enum 0 No
enum 1 Yes
default No;
# if both members are not servers, break
break not tor server 1;
If I comment out the break then things work as expected. 172.23.0.1 is a non-Mikrotik Zerotier node running 1.14.2, and it has the server tag set to 1. This means that the traffic should be allowed to/from that IP by the rest of the Zerotier network.