This vlan issue has had me troubleshooting for a while until i narrowed it down to the netgear switch M4300 on latest firmware.
I have the netgear switch configured as the main DHCP server for multiple vlans. I have have Ubiquiti AP broadcasting 2 different SSIDs on different vlans (vlan 1 and vlan 20). The gateway is Ubiquiti UDM Pro which has DHCP feature disabled connected to 1Gbps ISP line.
Testing on 2 SSIDs with Iphone 11 with WiFiman
SSID1 (Vlan1) shows download speed of 500Mbps on the iphone
SSID2 (Vlan20) shows download speed of 2Mbps on same iphone
Now I created new SSID3 (Vlan5), this time DHCP server on the Gateway. Configured DHCP relay on Netgear switch & No Vlan routing
SSID3 (Vlan5) shows download speed of 500Mbps
Switched to wired testing.
Computer on Vlan1 - download speed 500Mbps
Computer on Vlan30 - download speed 2Mbps
Final testing - reconfigured Vlan20 with DHCP on Gateway instead of Netgear. Delete Vlan routing for Vlan20 on netgear.
SSID2 (Vlan20) on Iphone jumped to 500Mbps
Computer on Vlan20 - download speed jumped to nearly 450Mbps
Conclusion is Netgear M4300 has some serious issues with Vlan Routing and/or DHCP Server for said Vlan.
If anyone has similar setup, I would be interested to hear back. I did some troubleshooting with an agent who saw the issues and took a copy of my switch config file for further investigation.
Model: GSM4352PA|M4300-52G-PoE+ - 48x1G PoE+ Stackable Managed Switch with 2x10GBASE-T and 2xSFP+ (550W PSU)
Thank you for sharing this issue that you have with the M4300. Please also give us an update on the progress of your case so that the community may also benefit from it.
