$ cat / var/ etc/ dnsmasq/ dhcpd.conf
dhcp-option=option:domain-name, "local"
dhcp-authoritative
dhcp-leasefile=/ var/ db/ dnsmasq.dhcpd.leases
dhcp-range=set:lan,192.168.10.128,192.168.10.191
dhcp-option=tag:lan,option:dns-server,192.168.20.100
dhcp-option=tag:lan,option:router,192.168.10.1
dhcp-option=tag:lan,option:netbios-ns,192.168.10.100
dhcp-option=tag:lan,option:netbios-nodetype,8
dhcp-range=set:lan,192.168.30.128,192.168.30.191
dhcp-option=tag:opt2,option:dns-server,192.168.20.100
dhcp-option=tag:opt2,option:router,192.168.30.1
dhcp-option=tag:opt2,option:netbios-ns,192.168.10.100
dhcp-option=tag:opt2,option:netbios-nodetype,8
This information shows the correct gateways for each subnet...
The range set seems weird to me (both lan).