DHCP Server - ip address leases have no host names

Question

_{Wednesday, May 19, 2010 12:30 PM}

Hi Experts

windows 2003 R2 server - dedicated dhcp server

in my address leases everytime i saw a bunch of ip addresses issued without host names

are these ip addresses legitimate can i setup or configure dhcp so it can not issue addresses without a hostname.

can i also prevent dhcp servcies to stop issuing ip addresses to ipods and phones

please advise

thanks

AK

All replies (5)

_{Wednesday, May 19, 2010 3:41 PM ✅Answered}

DHCP does not have that type of security built-in to the application.  You need to move your security out to the edge to prevent or filter these devices.  For instance, if you do not want iPhones or other mobile devices from obtaining IPs, implement an 802.1x solution which will require them to provide a certificate or atleast be challanged for credentials before being allowed on the wireless network.

The blank leases are devices that are not providing DHCP with a host name.  Again, take a look at those devices (you can find them by MAC looking up the MAC tables in your switches, if they are managed switches), then follow the cable to the device.  If these are wireless devices, again, you will need to put some security into the edge.

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_{Wednesday, May 19, 2010 11:31 PM}

  I agree with Jorge on this. DHCP is a very simple system which operates at a low level in the network. You cannot control it from the OS level. The client simply broadcasts a request on the network and the DHCP server replies with an offer. It is a convenience which cannot be used as a control measure.

Bill

_{Tuesday, May 25, 2010 8:45 AM}

Hi,

I just want to check if the information provided was helpful. If there is any update on this issue, please feel free to let us know.

We are looking forward to your reply.

_{Tuesday, July 24, 2012 11:39 PM}

In our environment we use both thin clients and VOIP phones. Both will show up in DHCP without host names and consiquently do not show up in DNS.

Better late than never!

TLM

_{Thursday, September 12, 2013 5:09 PM}

I have been seeing this lately on our Windows 2008 R2 DHCP server and the "problems" devices are DRAC/ILO device for Dell and HP servers.  Not sure why it is happening to these devices, as it did not happen before and then it seemed to of happened after we swapped out a management switches and changed the IP address of these RAC controllers.