Enable DHCP Failover lease behavior (one hour leases) on standalone DHCP server?

Question

_{Friday, January 29, 2016 6:45 PM}

So here's an oddball question about DHCP and public WiFi that relates to behavior I first saw in a DHCP Failover pair.

In the failover pair, I observed that DHCP clients would get a one hour lease before they would get a lease with the defined lease time in the scope. The DHCP clients were an unusual hardware device that normally required infinite leases... believe me when I say I don't want to get into the stupidity of that design... so they wouldn't tolerate the temporary lease.

I've since learned this is intended behavior in a DHCP failover pair, but I thought that would be an interesting behavior for a DHCP server used for public internet access to save on leases. If someone walks or drives by with a phone that has WiFi auto-connect on, it would grab a lease and then move on, wasting the lease until it expired. In a location with thousands of people passing through daily, this would eat up addresses quickly. A so-called 'temporary' lease would be a neat solution.

Is there a way I can get this behavior on a stand-alone DHCP server? I could set up a pair of servers as a failover pair, but some places that don't have enterprise agreements or Datacenter Server licenses wouldn't like having to pay for two server licenses just to enable this behavior.

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All replies (3)

_{Monday, February 1, 2016 3:08 AM ✅Answered}

Hi Gordon,

Thanks for your detailed description.

Based on my understanding, you wanted to achieve the goal: let DHCP clients obtains a temporary lease when they connected to the network, and when the leases expired, giving them a infinite leases.

If I misunderstood, please feel free to correct me.

>>Is there a way I can get this behavior on a stand-alone DHCP server?

According to my experiences, there is a workaround to achieve this goal.

You could allocate these devices a temporary IP address using a individually DHCP scope, giving them an one hour leases.

When the leases expired, you could give them another IP addresses with infinite leases using another individually DHCP scope.

On server 2012 and late version, you could achieve this purpose by using policies.

The following link describes how to use policies on DHCP server:

https://technet.microsoft.com/en-us/library/hh831538.aspx

https://technet.microsoft.com/en-us/library/dn425039.aspx

Additional resource about DHCP failover:

https://blogs.technet.microsoft.com/teamdhcp/2012/08/06/dhcp-failover-load-balance-mode/

Thanks again for posting on the TechNet forum.

Best regards,

Andy_Pan

_{Monday, February 1, 2016 8:27 PM}

Not so much offering these DHCP clients infinite leases (that was a different problem not related to this one), but I think I get what you're trying to explain: Use a DHCP policy to assign temporary leases to new clients and then longer leases to renewing ones. Or maybe use different scopes depending on the client type.

I'll see if there's a policy available to specify new clients vs renewing clients. At first look there doesn't appear to be a way to specify lease duration or specify a scope with a policy, though.

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_{Wednesday, February 24, 2016 7:40 AM}

Hi Gordon,

Did this issue was solved?

If not, you could give me more information and we could discuss it for further.

Best regards,

Andy_Pan