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I think this is a basic VLAN question but I can't find an explicit answer.

I have a wifi access point which is capable to broadcast multiple SSID's and configure VLANS (tagged).

My DHCP is a simple TP-LINK router with 4 LAN ports.

The problem is that, if I connect through wifi with a (tagged) VLAN, lets say PUBLIC, my client doesn't receive an IP-address.

So, although the VLAN's are configured at the access point, does the router need to have some special specifications to support the VLAN'S? If so; which ones?

Bonus question

If I have a switch which supports VLAN; does the router still requires the same sort of support?

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    If your router doesn't have any VLAN capabilities then it probably won't have any "IP Helper" features to allow your VLANed devices to direct clients to where your DHCP server is as it will have it's own IP address. Most SoHo equipment is simply not designed for complex network requirements such as VLANs.
    – Kinnectus
    Commented May 23, 2017 at 10:17
  • I had a similar scenario. I can't remember all the details because I needed it for security, and it didn't work the way intended.The AP will handle the VLAN, so even if your router can't it,it will do it. However, the VLAN itself is moot as everything still connects down to the router, and the router doesn't care about the VLAN, so everything will see the rest of the device. In short, the VLAN is nothing more than a front end spoof. To have a true VLAN network your router will need to have the same capabilities.
    – JustAGrump
    Commented May 26, 2017 at 14:21

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In short: If your DHCP is the router, and your router doesn't support VLAN, the DHCP will be unreachable.

Packets are tagged by adding a 802.1Q header in the Ethernet frame right after the source MAC. If your router doesn't support VLAN, it will not understand the packet (since it changes the Ethernet frame's structure) and will probably just discard it.

So, to reply to your first question: Yes, your router need to support VLAN (aka IEEE 802.1Q standard).

To reply to your second question, unless you have a level 3 switch, no. Each VLAN are separated networks (like a physically separated one) which should run on different IP networks. So, you need to have a router which can route your VLAN to the other network and forward the DHCP requests to the DHCP server (by configuring an "helper IP").

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