dhcpd(8): use UDP sockets instead of BPF https://www.undeadly.org/cgi?action=article;sid=20250613111800 #openbsd #dhcpd #tcpip #networking #udp #bpf #development #newfeature #testing #freesoftware #libresoftware

Next step testing #IPv6only operation in my local network, I wanted to give #dhcp "option 108" (IPv6-only preferred) a try.

I'm running #ISC #dhcpd on my #FreeBSD router/firewall, so I looked at the manuals:

https://man.freebsd.org/cgi/man.cgi?query=dhcp-options

Ok, added "option option-108 00:00:00:00;" based on that, which dhcpd rejected 🤔

From finding random different examples for custom options and with some trial and error, I found I have instead to declare the option:

option v6only code 108 = integer 32;

... and then use it like this:

option v6only 0;

Ok, what's up with documentation here? 🙄

At least it works, verified on my phone running #Android 14. No #IPv4-address from my pool any more. Instead, 192.0.0.4 appeared, seems it automatically configures a #clat...

What do you use to monitor that a subnet has a functioning dhcp server?

I am looking for an output I can put into #grafana and make an alert is there are timeouts or response is too slow.

#dhcp #dhcpd #grafana

@cnxsoft
Ugh official/recommended #dhcpd replacement uses a configuration file format that does not allow for comments 😕
#json isn't a good format for humans

I spent the initial portion of the morning mucking with #dhcpd so that one of my ethernet devices could assign a fixed ip to the #XR18 simply so i could use the mixer (X Air Edit) on my desktop. Big fun.