[Dnsmasq-discuss] tagging hosts that don't provide client ID

[Paul Chambers]

This is a bit off-the-wall, but I thought I'd ask...

I'd like to allocate hosts to a separate DHCP range if they request a 
DHCP address, but don't supply a meaningful client ID (either missing, 
or a MAC address as client ID).

The reason being that when our network monitoring shows a machine has a 
problem, if it does not supply a meaningful client ID/name, it's 
difficult to track down who to ask about it. While our company is still 
small enough to collect hardware MAC addresses of every physical 
machine, many machines are also running virtual machines too, so it's 
not practical to maintain an exhaustive list. And it's often the virtual 
machines that go unnamed - and later cause problems.

One way to encourage/remind users to 'name' their machines is to treat 
the unnamed ones as inferior citizens. I was thinking of putting them in 
an IP block that has severely throttled internet access.

The most logical way I can think of is to tag them with a network-id, 
though I don't see a way of automatically assigning some kind of 
'noclientid' tag without patching the source. The only thing I can think 
of is periodically parsing dnsmasq.leases, and generating a config file 
containing a dhcp-mac line for every entry that doesn't have a 
meaningful client id. But that would happen long after the fact, and 
unless I also prevent such unnamed hosts from renewing the IP address 
they already were given, they won't be forced to the throttled IP range. 
Seems fugly.

Is there a better way?  I'm inclined to create a patch, if no-one has a 
better idea.

-- Paul