DHCP service isn't giving out internet addresses right now.
DHCP service isn't giving out internet addresses right now.
Dear Community, We have a network service called DHCP installed on two computer servers running Windows Server 2019. These servers are also Domain Controllers (DCs) and act like the bosses of our computers. There are actually two Domain Controllers here: one named ho-domain and another named ho1-domain. Everything worked fine until yesterday when we bought some new HP laptops to use them, but suddenly something went wrong. Yesterday, it could not give out IP addresses to those new laptops. Later, all devices started having the same problem where no old device was giving out an IP address even though they were trying to hand over a new one. We tried several steps, but now DHCP is still running and showing no strange errors or crashes. The only thing it did was stop handing out IPs to client machines instead of letting them get new ones.
We rebooted the Domain Controller ho-domain (which had the DHCP role). Then we restored the DHCP service using a backup file from one day ago on the ho-domain machine. We thought maybe the server itself was broken, so we took the DHCP role off ho-domain temporarily. Next, we put the DHCP backup back on the second Domain Controller ho1-domain and turned it on properly. It seemed fine then, but the problem wasn't fixed anymore. The issue was still there: no IPs were being handed over.
Since our Domain Controllers are virtual machines (VMs), we rebooted the Base Machines where these VMs live too. Then, we isolated our network so that if a Switch or another device in between caused the problem, it would be bypassed, but it still didn't work. Next, we installed the DHCP Role on a third Machine which was a separate physical computer running Windows Server 2012. We could not restore it using the DHCP backup because of course we had to manually set up scopes and everything else. It only managed to give out a few lease times but all in good order. But once we tried to manually save IPs that hadn't been leased yet, things started going wrong again. Not just all reservations became inactive, but it also stopped giving out new IP addresses altogether.
Then we installed the DHCP Role on another other Physical machine and this time we did not reserve any IPs at first. The DHCP server is now only offering leases without manual reservations against our specific MAC devices. We had a fear that configuring DHCP again would cause weirdness and stop working for all of us. Now, I need your help because I don't see any major events in the DHCP Event Logs and I really don't understand how to fix this issue. It is very frustrating. Please help me out with this situation. Thanks.
How many old gadgets on my network use DHCP addresses? How many devices use static IP addresses? Can I ping those static ones? Is anyone online right now? How many new laptops did you buy? Did you set up these new computers correctly for my existing setup? What is the list of free addresses available from my DHCP server? How many specific numbers do I need to reserve for special tools? Draw a simple picture showing all the devices and how they connect. Write down each device's name, MAC address, and IP type along with its real IP number. Check if there are any loops or wrong connections on the network. Look up what my router is seeing using "arp -a" to get full details. Fill in a big picture of my whole network so I can see everything clearly at once.
Thanks for getting back to me, but basically, my server says "no" when trying to give out an internet address. I looked at the traffic using Wireshark and found that the client is asking for a specific IP, but the server isn't giving one back. Could you explain why this is going on?
I know very little about running a Microsoft Domain Controller as a DHCP server, so my advice will be basic. I'm not sure exactly how you are using DHCP. When you say the server is denying DHCP requests, does your PC try to ask for a specific IP from a certain server address? Usually, when this fails, the PC goes into "stupid mode" and sends out a broadcast asking for any available IP. Does the server respond to that request and give back an IP that isn't working? If you have set static MAC addresses on your IPs in the DHCP server, that part I don't know about. Microsoft changed how domain servers work since my last time fixing them years ago.
You can check two or three clients that aren't getting their IP address by running "ipconfig /all" and sharing what you see. Then run "arp -a" on both the client computers and the DHCP server. From the server's side, tell us which IP addresses are allowed for new devices, how long leases last, any fixed or reserved IPs, and if there are logs that show why certain addresses weren't given out. The server might be set up wrong, broken, or just decided not to give out an address at all. Ask if there are routers somewhere on the network too.