DHCP Option 78 & 79 not working consistently

[Dael Sutton]

I've just set up a failover pair of pfSense machines to handle the DHCP for our vlans, and for two of them need DHCP option 78 (slp-directory-agent) and 79 (slp-service-scope) set.
Our existing ancient WIn2K3 server (that I am wanting to replace) has them working in an arcane entry fashion, and another Centos box has them entered in dhcpd.conf as well, and is working.

On pfSense I have option 78 set with 1 xxx.xxx.xxx.xxx as text (where xxx is the IP of the slp agent server) (and the 1 is the boolean for true) and it doesn't come through properly, and option 79 set as 1 BHS-SCOPE (our scope name, and again a 1 for the boolean true).

old Centos has true xxx.xxx.xxx.xxx and true BHS-SCOPE in it's dhcpd.conf file.

I've tried varying methods (1/true ip/fqdn) and as text/string objects and it doesn't get to the clients consistently. Am I trying to do something that isn't fully supported yet?

Regards,
D.

[Dael Sutton]

Found that a) the options need to be set in bytemasks ie 78 needs to be 05 01 AC 10 00 53 (length, boolean, IP of server) and 79 needs to be 0A 01 42 48 5E 2D 53 43 4F 5D 45 (length, boolean, name of scope) for it to work, and b) turn DHCP server off on the failover machine. There seems to be a bug when CARP is enabled that the second DHCP server will return garbage instead of what's configured in the SLP options.