How to advertise mutiple routes via (pihole) DHCP?

[deHakkelaar]

You can push as many as you like:

Pihole DHCP: push a static route to clients

You can use the classless-static-route DHCP option but you will need to push the default route as well through this option. In below example, 10.0.0.1 is my router and I am adding a route to 206.189.252.0/24 via 10.0.0.99. pi@noads:~ $ man dnsmasq [..] -O, --dhcp-option=[tag:<tag>,[tag:<tag>,]][encap:<opt>,][vi- encap:<enterprise>,][vendor:[<vendor-class>],][<opt>|option:<opt- name>|option6:<opt>|option6:<opt-name>],[<value>[,<value>]] Specify dif…

EDIT: Ow that link is a bit old.
You can see a list of DHCP options with below now:

pi@ph5b:~ $ pihole-FTL -- --help dhcp
Known DHCP options:
  1 netmask
  2 time-offset
  3 router
[..]
121 classless-static-route