Query a DHCP server for a specified IP Addres to obtain MAC and hostname

Shane Kahkola

I have searched several forums and found various flavors of my issue. However, I can't seem to get good resolution. So here's the problem:

I am writing an app that collects IP Accounting data from Cisco Routers. The app collects only the Source, Destination, bytes, and packets. All of this information is stored in a SQL database.

The output of the IPA data is timed (Cisco cron jobs). My IPAHandler needs to be able to resolve IP Addresses to host names. I am doing this with some releative ease, until it comes to local IP Addresses of machines that are not joined to the domain.

We are a college and we have several "rogue" notebooks on wireless. We would like to be able to capture the machine name of each device that gets an IP address - subsequently we would have their network usage data. But if I try to use the code listed below I get an error:
===========
string sName = Dns.GetHostEntry(IP).HostName;
===========

Our AD only allows secure updates, so they don't show up in DNS and I get the following exception:
===========
No such host is known.
===========

Here's the question:

Can I query the DHCP server (an AD Domain Controller) for the IP Address and machine name? If so, do I need to use a WMI query, or is there an API I can use?

2 Replies

Know the answer? Post it — somebody with the same question will find it here.

Shane Kahkola17y ago
No, you are not correct. While I did not mention the MAC address, I assumed that I would be able to obtain it if I could also obtain the hostname, as I realize that the MS DHCP server logs all of those details.
Furthermore, I find it a fantastic turn-off that the only reply I would receive to my question was someone accusing me of being misleading. If you don't like my post, how about simply asking me to ammend it instead of accusing me of something that was unintentional (in terms of misleading)?
0
Sam Hobbs17y ago
Your subject says MAC address, but your question says nothing about MAC address. Am I correct that the MAC address in the subject is extraneous and misleading?
0