Unifi / DHCP issues

[jblackburnHWGA]

I have a very odd issue after returning from xmas and i can't quite figure it out.

I have an old unifi setup and have removed AD. I just have a server with DHCP and a bit of DNS on. I'm getting a new school built which we're moving into in Sept so I'm trying to keep what i have alive.

 

My ssids link to VLAN then DHCP assigns addresses. Works or did lol. For staff, sixthform, IT and my staff BYOD, i've got no issues. connects without fails every location every AP. DHCP reflects this. I can ping DHCP from my APS. The issue is for my Chromebooks SSID and iPad SSIDS. i can't get ips on all devices. I just get 169 addresses. I get them in some locations and not others.

 

I've traced through everything today and found no fault. No vlan missing from a switch. No errors. I'm starting to rule out a network issue completely. I think its DHCP but again can't see why. Any ideas on diag i might have not thought of.

 

I had a hyper-v fail on the 27th Dec which wasn't rectified until yesterday. When i tested yesterday i didn't spot the issue but its only an issue for student devices.

 

The thing thats annoying is i can go into W105 and connect to the ipad ssid without issue. But if i go down to W108 i can't connect. Both the APs are on the same switch same config.

 

Also we have 1 to 1 computing which is 1000 student devices banging around the school. The fact the teachers and sixthformers are fine means i can't just switch it all off and on again and hope for the best. I'm trying to be tactical in my resets.

[speakercon]

Don't suppose the scope is full?

 

If you set a static on a chromebook/ipad does it then connect okay?

[jblackburnHWGA]

Scope is reporting its ok and there's no events contradicting it in event viewer.

 

If i set a device static it doesn't connect to anything. Just testing the same thing on a laptop rather than an iPad. I'm waiting for the best time to give the DHCP server a restart

[speakercon]

Hmmm, can you see free IP's in the address leases?

 

I once saw a similar thing with iPads after they started randomizing the MACs after the update which resulted in multiple leases for the same device over time and quickly filled up the scope.

[ZeroHour]

Does it happen for any other devices?

I am just thinking a laptop with wireshark trying to see if DHCP is being issued correctly.

 

What versions are your unifi setup and what is Network running on?

[jblackburnHWGA]

Just set a laptop with a static ip for one of the affected SSIDs and it can't ping anything. My other SSIDs are ok. Just the three student ones. I had intermittent connection this morning buts it now ground to a halt.

 

Currently on 7.1.61.

Edited January 9, 2024 by jblackburnHWGA

[jblackburnHWGA]

Figured this one out almost. Its a switch i have routing half the site to the core. I'm currently rerouting to bypass it then will reboot and see if its figured it out. Its blocking data to certain vlans like they don't exist by they do. No errors and i can't spot the problem.

 

Another issue of no address at all on a certain vlan was caused by me. I accidently turned off the dhcp relay for three vlans This is what happens when you don't use your brain for 2 weeks over xmas.