Had an odd problem last night, dnsmasq stopped giving out addresses via dhcp - its never done this before, and only recently updated to 21.02.0.
The only error given in the log is daemon.err dnsmasq[5643]: failed to load names from /tmp/hosts/dhcp.cfg01411c: Permission denied where that file is rw by root only, and it exists.
The only other error is the very strange kern.warn kernel: [ 5626.058224] enter showtime, cell rate: 0 - 2094, 1 - 2094, xdata addr: 0xa1cf0000 - a google search don't show this as connected. Its an error that only happens on xrx200 devices, and quite often with plus.net - both of which apply to me.
Anyway strange with with dnsmasq, is after a few hours it settled down, and started giving out ip numbers. The ADSL line kept on going up and down over night.
Now that dhcp is working again. The file is still rw for root only, and as its in /tmp its a file that is created on the fly - and by the date on the file, it must been soon after poweron. No I've changed no scripts - only removed /etc/modules.d/ipt-nat - as I do firewall via nftables.