DHCP Option 82 not working


#1

What am I missing to get Option 82 working? On the AP, we have turned on Remote ID Type to “CPE Address”:

I then delete a DHCP reservation in our Mikrotik for a customer, reboot his router (to force a new request) and when I look at the new request, there is no Remote ID:

I feel like I am missing something obvious. We are running Firmware 2.4.1.2-beta-4 on the AP and 2.4.1.1 on the CPEs.


#2

Found our issue. There is a spot to also turn on Option 82 under Wireless - SSID settings in the AP. We missed that one completely.

We did need to set the Encode Type to binary to get it to work properly with Mikrotik but all is operational now.


#3

That’s good to hear! Sorry that I didn’t get to this thread quick enough to help you out.


#4

@Chadwick now that you have it running as you would expect, can you try deleting the DHCP leases on your DHCP router and see if the Circuit and Remote IDs are still passed to it on the renew cycle?

When I do so, all of the renew requests do not come with Circuit and Remote IDs. Only new requests include them. I previously opened a ticket about it, but they couldn’t replicate it, and I really couldn’t take the time to prove it at the time.


#5

Hmmm, I’m hesitant to do that after reading what you are saying… I have not seen that yet but I have not removed an IP assignment yet. I try very hard not to monkey with customer links and deleting an assignment tends to cause issues on the customer end until they reboot or renew. We are at a 24 hour cycle for leases.


#6

Why not go for shorter lease times? Not like DHCP takes all that much bandwidth or CPU resources, then if Winnie the Pooh hits the fan it is around 2.5 minutes max before someone gets back online…


#7

There are good and bad reasons for shortening DHCP leases. The Option 82 problem I described above exists either way.

[One of the largest benefits to longer leases is during failures… if your devices retain their addresses while somehow disconnected from the DHCP server, it can ease troubleshooting and identifying various problems.

When troubleshooting or changing network configurations, I’ll shorten leases in advance so the transition happens relatively smoothly / quickly.]


#8

I tested it again. I removed 25 leases, and only 4 came back with Option 82 information (The G2 routers). I’ll see if I can open another ticket to get this sorted.