How to fix DHCP server after main switch replacement
I am a computer science teacher in a small school who is getting to grips with a role as server/network admin. Today, we all lost internet connection and were unable to access the server remotely.
It turned out a main switch an (HP2530 series 48port) in the server room had failed and luckily we had another similar one sitting around. I switched the connections over and we are up and running except:
Many users are having difficulty connecting using DHCP, I suspect the DHCP server has stopped giving out IP addresses. Our server is running Windows Server 2012.
Are there any suggestions of how to troubleshoot this issue? I can now access the server, both remotely and physically. I connect devices to the network if I use a static IP but I would prefer it to just work via DHCP.
Thank you all...
A DHCP service restart hasn't fixed the problem so I will look into resetting the replacement switch in case there were existing settings affecting the DHCP service.
I have also now reset the "new" switch back to factory settings but the problem still persists. Users can join network but do not get an IP address unless they manually set one. Strangely this affects Mac users more than Windows users. Windows users who have existing IP address continue to be able to connect while Mac users have to add IP address manually.
Wireshark shows that DHCP does advertise itself but Apple and Linux devices are not getting IP addresses over wireless. I get a warning from the DHCP event log "This computer has at least one dynamically assigned IPv6 address.For reliable DHCPv6 server operation, you should use only static IPv6 addresses." Could this be related to the problem?
I have also tested a Windows 10 device, it is able to release and renew its IP address using DHCP. All the Apple devices in the school which are mostly BYOD and so have various configurations are not able to get an ip address via DHCP over WiFi or wired connection. Linux devices are having the same problem although previously connected devices were initially able to connect over Ethernet. This is not normal, does anyone know what is the difference between Unix-based devices and Windows in this regard?
This is proving a real problem, we called in the IT comapany who originally set up our network to log in remotely, set up our new switch and check our system. They can't work out what the problem is either. We can't work out why Apple devices can't connect via DHCP and Windows devices can.
Solution 1:
- Do factory reset of that switch, see will that solve your problem
- get a small 5 port, "dumb" switch and connect it directly to you DHCP server and test it, if problem persist, Download Wireshark and check does your DHCP server advertise itself.
- Check event logs on your DHCP server
Come back here :)