I manage a network behind a Dell SonicWall (DHCP Server), with 4 switches, which has 2 wireless access points to provide mobile/wireless communication to our warehouse and sales staff and a wireless router hooked up to the cable modem to provide isolated guest access to the internet. ~50 networked devices in total with an IP pool of 80 addresses reserved for Dynamic DHCP 174-254. Others 2-173 are reserved static addresses.
Both access points have been working for over a year with the current configuration. No settings on the network have been changed. When the issue occurs signal strength appears to fluctuate dramatically on both access points, the wireless network becomes sluggish to just the wireless devices, wired devices connected to the same access point are not affected, and then the wireless devices are later dropped. Upon attempting to reconnect on any device, it receives random error messages when trying to connect to either wireless access point, such as unable to connect, invalid password, or being able to connect but unable to use the network after. Connecting via ethernet cable works fine.
I have updated to the latest firmware for all Wireless routers, even attempted beta firmware. I have lowered the RTS (1500) and sending frequencies (50ms) to see if it may have been interference/too many clients with no change. Renamed SSID's to ensure no other PCs were attempting to connect. Changed wireless channels - though no other buildings are within 1,00ft of the building. I have tried hard and soft reboots. Even relocating the wireless routers.
When disconnected from the network the WiFi operates normally. All routers use WPA2-Personal/AES no key rotation. I took the known functional Wireless router and switched it to an access point reserving it's IP address etc as the other Access points and encounter the same issue, revert back to a wireless router directly to the modem and works fine.
While troubleshooting toward the end of the day both access points were functioning normally with no issues connecting.
My guess currently is that the DHCP server isn't serving an IP address due to possible network load, causing timeouts while connecting, but wired or wireless should be pulling from the same DHCP IP pool.
There are four other situations that could be a factor.
1) A new device was added to provide Ethernet connectivity to a postage meter that was connected end of day the day prior to the issues occurring. It supposedly offers wireless connections though I have not researched it as it was not needed.
This was disconnected today to troubleshoot the issue.
2) A PLC is undergoing UDP packet testing in order to validate sending/receiving UDP packets from PC to PLC and vice versa
3) A construction crew remodeling tore down a wall that may have had network cable running through it.
4) I have recently begun to see a Netgear wireless router in the list of wireless access points.
Any help troubleshooting would be greatly appreciated.
More about :intermittent wifi connectivity networked access point
I tracked down the issue, effectively too many unauthorized wireless devices were connected. Once I changed the password/SSID I had a lot of requests for the new password that shouldn't have been connecting. Haven't had an issue since.