I recently upgraded a CentOS 7 vps running openvz to zerotier 1.6.4. After the upgrade zerotier would no longer start, complaining about not being able to open the tun device:
$ /usr/sbin/zerotier-one ERROR: unable to configure virtual network port: could not open TUN/TAP device: No such file or directory
The permissions on the tun device appear correct and the tun module still appears to be enabled in the kernel.
$ ls -al /dev/net/tun crw-rw-rw- 1 root root 10, 200 Feb 23 06:44 /dev/net/tun $ cat /dev/net/tun cat: /dev/net/tun: File descriptor in bad state
I noticed that if I prevent zerotier from dropping privileges (-U) it will start, but it will remain in TUNNELED mode. I ruled out any iptables issues by disabling the firewall. Everything is functional in tunneled mode, just slow.
Are these known issues? Are there any suggestions for how to further troubleshoot?