Using DHCP Option 43

If you've ever had to work in depth with DHCP, you've probably worked with the common options. But even the pros can find it difficult to work with Option 43...

EXTRA CREDIT:
- I mention it briefly, but the default method most network controllers use to announce their presence on a network happens at layer 2 of the OSI model. IP runs at layer 3, and both DHCP and DNS run at layer 7.
- This means that the default method can work even when devices don't have an IP address, but it will only work as long as the devices and the controller share the same layer 2 network--and they may not! That's when you need to use alternative techniques to point the devices towards the controller.

[stefanneuberg]

There’s a crowd I know that needs to hear this one, fantastic!

[petervandebeek]

What about Option 132 to get your thones to their Voice VLAN. That's also a life saver. Especially if you don't are the one who is controlling these phones, but wants to get them to the right VLAN, since you do the network for that customer.

[grimsysadmin]

I use option 43 for the inform url for unifi gear. The biggest pain is just knowing how each vendor implements setting up options in their respective DHCP servers. We've documented how to implement it for the various routers we sell/deploy for customers