Connect Two VLANs to Database Server – How to Guide

If you assign switch ports to specific VLANs, the switch treats them as if they were all in their own little Ethernet network, and the end stations are usually unaware that they're connected to a VLAN-based switch.

If a switch port is tagged, that means that all of the frames that aren't in the default VLAN (usually 1, which you're right to leave alone) have a 4-byte 802.1q header attached that says what VLAN they go with (as well as basic QoS information). A device attached to a tagged port needs to be aware of the VLAN setup if it's going to properly process such packets, but these are typically other switches (either traditional switches or software switches inside a VM hypervisor).

You should usually force end-user ports to untagged to ensure that someone can't insert a custom VLAN tag and get access to a different VLAN (known as VLAN hopping). On your switch, all of the ports should be untagged unless the WiFi APs are capable of talking on multiple VLANs so that they can have a management address on a different VLAN from the one they're sending client traffic over, or so that single APs can connect multiple SSIDs to different VLANs.

Whether a "basic" switch "handles" VLANs depends on what each term means. Most unmanaged switches will simply pass 802.1q-tagged frames along as-is, with no attempt to direct them anywhere in particular, so plugging an unmanaged switch into an untagged port is simply the same as not using VLANs at all, while plugging one into a tagged port is like having a shared tagged segment among the different equipment that knows about the VLANs.

Judging by your switch, I'd say you don't have the budget for a real ethernet tester like those from Fluke Networks.

Your switch is Layer 2 (L2) only and doesn't support routing, so you'd need an external router (L3) to move packets between the VLANs. I would conjecture that your random network issues were caused by either bad cabling or mismatch on speed/duplex between the switch and your systems.

You can look at using iperf configured on a server, and then have each of your client computers run a test from their respective ports to the server (one at a time), then look for interface error counters being incremented to help isolate any issues or misconfiguration.