I have an Active Directory network consisting of a Windows server 2019 domain controller with DHCP and DNS on it too. New clients on our network are failing to obtain IP Addresses from the DHCP server, but clients which have recently used our network are working and are able to access the network just fine. I tried to run ipconfig /release and then ipconfig /renew on the new windows clients in CMD but all I get is An error occurred while renewing interface Ethernet : unable to contact your DHCP server. Request has timed out. The same thing happens to wifi adapters too. I recently removed another Windows Server 2019 dhcp server in a failover configuration from the network. the DHCP role is completely removed from that server. I also recently ran Windows Update on the server, and right about then is when the problems began. The working clients are able to ping other working local clients, servers and also the internet. I have pinged both ip addresses and FQDNs, so I do not believe there are any issues with Windows Server DNS Server. I have looked at a post on Spiceworks about a similar issue, which you can check out here, and have tried every single fix that every user in that post mentioned, but no luck. I have tried multiple times to unauthorize and reauthorize the server, restart the DHCP service, reconcile the scopes, but still nothing works. The server which DHCP runs on is able to respond to pings from working clients, and Windows firewall is open for incoming DHCP requests. I had a few scopes that were full, but there were plenty more scopes with plenty of IP addresses ready to go. I also deleted as many old leases on the full scopes as I was able to, so there are currently no scopes that are anywhere near full, but still no luck. All I want is a working DHCP server.
I am at a complete loss of what to do. I have spent hours on this, with no new ideas or progress.
I appreciate all of your help.
Best Answer
You mention having multiple scopes and that some of those scopes had available ip addresses, as if a DHCP client will get an ip address from any available scope, and that isn't the case.
You need to narrow down the problem. Are the DHCP clients on different on different networks from the DHCP server? If yes, do you hace a DHCP Helper configured on your routers?
Run a packet capture on the DHCP server and on one of the affected DHCP clients and then run ipconfig/release and ipconfig/renew on the DHCP client and look at the captured traffic on the DHCP server and the DHCP client. Makre sure to filter the captured traffic to only show DHCP traffic. That should tell you what's happening.