Hey everyone! I'm facing a dilemma with our centralized DHCP setup. We have a single DHCP server that handles requests from over 100 sites, each with their own subnet. The issue arises when a user travels between three of these sites: we have to manually clear their lease from the previous site's subnet before they can get a new lease at the current site. I was wondering if there are better solutions than just setting the lease time to 15 minutes at each site? This is all running on a Windows 2025 server. I'd appreciate any advice or tips on how to streamline this process. Thanks!
5 Answers
You have a centralized DHCP server for 100+ sites, which is already a lot to manage. Manually clearing leases for one user is just a symptom of larger potential issues. It might be worth considering more local DHCP setups to reduce single points of failure.
But they didn’t say that it wasn't set up with high availability or failover measures.
Each site should really have its own local DHCP server in case the connection to the main server goes down. Plus, if the PC isn’t releasing or renewing its lease properly, it might also be a driver issue. Consider setting up a task that triggers a renewal on reconnect events. You could create a scheduled task that calls a release/renew script when a specific event occurs.
Why not just create a batch script for the user that runs 'ipconfig /release' when they're ready for a new IP? That way, they can trigger the release when they switch sites.
And you can throw 'ipconfig /renew' in there too! Maybe even set it to run at startup so they get a new lease every time they boot up at a new site.
That's a great idea! Just make sure it's scheduled to run each time they log in.
Use Wireshark to monitor both client and server. If the client tries to renew its lease from an incorrect subnet, the server should send a DHCP NACK, forcing the client to request a new IP. Also, just a heads up, server 2025 has had its share of issues—consider downgrading to 2022.
That's pretty misleading regarding NACK usage in this scenario, plus support for 2022 is ending this year, so that's not really a solid option.
If your user connects to a different site, the VLAN IP helper should allow them to grab a new IP from the correct scope automatically. Are you experiencing issues with that?
Wouldn't the DHCP server recognize the MAC address and assign the same IP again since it's the same server? Am I misunderstanding something?
Actually, it's not just a single point of failure; it's at least two points—if the server goes down or the VPN fails, you're in trouble.