linux routers need to enable DHCP relay/helper configs

[sarcasticadmin]

Description

The previous routers provided DHCP helper functionality for various vlans on the network. We need to make sure the linux based routers are capable of doing the same.

AC

• Linux routers support DHCP helper functionality across necessary VLANs

[sarcasticadmin]

Announcement from ISC when they deprecated the isc-dhcp at the end of Q1, 2022: https://www.isc.org/blogs/dhcp-client-relay-eom/ Additionally they called out in the post: "ISC is also considering developing a new relay based on Kea DHCP code."

In no particular order heres what Ive found as alternatives from the above article's suggestions:

1. https://gitweb.git.savannah.gnu.org/gitweb/?p=dhcp-fwd.git - A fork of isc-dhcp-relay from 2014, used by OpenWRT
2. https://github.com/opnsense/dhcrelay - openbsd implementation but seems BSD specific
3. https://gitlab.isc.org/isc-projects/dhcp - Just use isc-dhcp-relay

[owendelong]

After reviewing the available options, I came to the conclusion that the current state is rather abysmal.

I did find two additional options, neither of which has much to offer.

1. The Savannah fork -- offers no significant advantages over the deprecated ISC code which is still maintained-ish in most of the mainstream OS packages.
2. Opensense -- Not just BSD specific, but rather tightly tied to Opensense (which is closely related to PFSENSE) which is a horror show I wouldn't wish on anyone.
3. Just use ISC -- Deprecated code in a security sensitive role, what could possibly go wrong? Pretty much the worst possible choice except for all the others.
4. First additional option: DNSMASQ -- Very limited configuration options and not well suited to our environment, plus, well, DNSMASQ. UGH!
5. Second additional option -- dhcp-helper -- A project which appears to be one mans effort at solving a fairly specific use case without a lot of consideration of the wider world. Likely not well suited to our environment, but so far, I haven't found sufficient documentation to tell definitively, which in itself is not a good sign.

As such, I vote for Rob's option 3 (which is also option 3 in my list above).