[Dnsmasq-discuss] No new lease for Option 82 requests until old one times out

[Joachim Nilsson]

Hi Simon,

I've found a little problem with how Option 82 circuit-id/remote-id 
works. Everything is fine in the below setup until I replace the client 
with a replacement unit that has a different MAC.

     [client]---LAN1---[dhcrelay]---LAN2---[dnsmasq]

dhcp-range=subnet0,tag:!static,192.168.2.100,192.168.2.199,255.255.255.0,864000

     dhcp-circuitid=set:cid0,"Eth6"
     tag-if=set:static,set:tag0,tag:cid0
dhcp-range=tag:tag0,192.168.2.99,192.168.2.99,255.255.255.0,864000

When 'client' is replaced the request from the new client reaches 
dnsmasq, which responds with "no address available".  I figured this is 
because the "pool" for the static IP only has one entry, bound to the 
old client's MAC.  Indeed, it is not until the lease for the old client 
times out that the new client receives an offer. I guess this behavior 
is by design ...

I was thinking that adding 'tag:tag0' to the --dhcp-host setting would 
have been perfect for Option 82, since they're basically static leases 
anyway -- the same port on a given switch should always receive the same 
IP ... so adding tag support, in addition to the already existing mac 
and client-id, seemed at least to me useful.

What do you think?

Regards
  /Joachim