The dhcp server does not listen or respond on VIF interfaces (e.g. eth6.42)
If the file /etc/default/isc-dhcp-server is edited by hand by changing the INTERFACES="" parameter to contain the interfaces then the DHCP server works correctly. This fix is temporary, as the dhcp_server.py script overwrites the configuration files when there is a change to the dhcp-server configuration in VyOS
The best solution that I can think of would actually be to add the options in the cli for "linterfaces" and allow it to have multiple interfaces listed. Something like the following:
service {
dhcp-server { interface eth0 eth1 eth6.42 shared-network-name IRC-Chat-Test { description testing-eth6.42 subnet 172.16.24.0/24 { default-router 172.16.24.1 dns-server 8.8.8.8 dns-server 8.8.4.4 range IRC-Test { start 172.16.24.100 stop 172.16.24.111 } } }
This listen Interface should be an optional setting. If interface has a value the /etc/default/isc-dhcp-server should be updated with the falues to make the file look like
INTERFACES="eth0 eth1 eth6.42"