vyos@vyos# set service dhcp-server shared-network-name LAN subnet 192.168.1.0/24 domain-name private Invalid domain name (RFC 1123 section 2). May only contain letters, numbers and .-_ Value validation failed Set failed
The line is validated by https://github.com/vyos/vyos-1x/blob/ede8217b6345b58da85f68ca024b54e04fd6348c/src/validators/fqdn
We probably should adjust that regex to the same one we use on system domain-name which is [A-Za-z0-9][-.A-Za-z0-9]*