server 2012 and Cisco ASA-5506

What issues are you having?

Hi Manny,

Was there any changes made before you started getting these DHCP errors?

Make sure the interface in the firewall doesn't have DHCP set to it or is a DHCP server in itself since the server is the DHCP server.

You can follow some references that may help here:

https://community.spiceworks.com/topic/251943-bad_address-in-windows-2008-dhcp-server

Hopefully there are not multiple DHCP servers on the network. (I presume not, as Windows Server historically would disable its own DHCP server when it noticed others) Have you tried restarting the DHCP server? You also should restart systems on the network. (Would be a good idea to do after hours) I also happen to believe in keeping static IP addresses out of the DHCP scope. Whether you do it by range (my preference) or by exclusion is up to you.

I'm looking at the DNS suffixes. Seeing what implies local government looks very suspicious (unless that is your client). Also might want to give more information on how the network is laid out, which will help make things clearer.

BAD ADDRESS Means you have conflicts, multiple hosts already think they have that DHCP address and the DHCP server foesn't remember them.

 clear out all of the bad addresses, set up a second DHCP range for your network (if possible) and got on the local servers and use

IPConfig /Release&&IPConfig /Renew

Select allOpen in new window

Along the lines of the above, have you set up a number of devices with Static IP Addresses in the same range as your DHCP server?  That would cause the above.

The only time I tend to see these BAD ADDRESS entries if when clients are connected via LAN and WLAN.

To discount the ASA....

show run | incl dhcpd

And make sure it's NOT activated on the LAN/Inside interface.

Regards,

Pete

My guess is they rebooted the DHCP server.

You have a ton of statically assigned DHCP addresses, you should just change those systems over to Static IPs if they are not laptops that regularly leave the network.

Keep your DHCP range at about 2x your expected number of DHCP client systems too.

First, I would scavenge old stale DHCP records then release and renew the IP address as Ben stated.

Start from here then narrow it down.

Can the devices get IP address now?  If yes, then your DHCP lease time may have been set too long or stale records were taking up the DHCP pool.

Ok, Few thoughts based on my experience.

You stated "Windows Server has been configured as DHCP server"
I'm guessing you are having only one VLAN. But I have a few questions.

Did you set the ASA to relay your DHCP server towards your server?
What type of switches are you using a regular or smart switch?

Bad_address mostly of the time is caused because of lease time. Let say you have a machine with a dynamic address of 192.168.1.50 Then the server is trying to offer you that address it will place it as bad_address cause is being in used.

Solution, I know ASA 5505 has a DHCP limit just make sure you are relying on the DHCP to the right address.