Porting config from radvd and dibbler to odhcpd

Installing and Using OpenWrt
1

In our setup radvd and dibbler allowed /80 subnets to work without problems, I'd like to move this dhcpv6 server from a linux box into an openwrt router, so far I wasn't able to come up with the correct odhcpd config. Below are the two config files for both radvd and dibbler. What would be the correct odhcpd analog to this?

/etc/radvd.conf

interface ztDDDDDDDD {
    AdvSendAdvert on;
    prefix fcNN:NNNN:NN::/40 { };
    route fcNN:NNNN:NNCC:CCCC:CCCC:de::/96 { };
};

interface enp2s0.6 {
    AdvSendAdvert on;
    AdvManagedFlag on;
    prefix fcNN:NNNN:NNCC:CCCC:CCCC:de:ca::/112 { AdvAutonomous off; };
};

/etc/dibbler/server.conf

iface "enp2s0.6" {
 class {
   pool fcNN:NNNN:NNCC:CCCC:CCCC:de:ca::/112
 }
}

I'm aware that subnets smaller than /64 on ipv6 are bad since they break SLAAC and other stuff, but the /80 subnet I'm working with is a limitation of the technology already in place, designed originally to work with docker autoconf, that only requires a /80 subnet. Thanks for understanding!

2

At least a /80 but why not just give it a /64 ? You're using ULAs so you have 65536 prefixes size /64 to work with

1 Like
3

/80 is what is delegated to the openwrt router by the sdn software were using, nothing larger. I'm aware of how hacky this sounds, but this is why I'm reaching out to this community! I can't seem to figure out how to do subnets on something smaller than /64 with odhcpd.

4

it's because doing subnets smaller than /64 breaks all the standards and openwrt is standards compliant. You break it, you buy it :wink:

NOTE: I'm not saying it can't work, just that no-one has any experience with standards-broken networks.

1 Like
5

Thanks for the interest but you're not being helpful at all. Will post back if I find a solution.