A question about Guest Network Pro, VLANs, and tagging

[Seth Harman]

I'm relatively new to VLANs so forgive me if this is a dumb question, but I've been searching everywhere for an answer to this question and I can't find one. I've upgraded my RT-AX88U Pro (main router) to the firmware that supports Guest Network Pro (the AiMesh nodes do, as well) and I've created a Guest Network Pro IoT VLAN with the ID of 53 and the address space of 192.168.53.x. Please see the following scenario:

Wired client -> Managed Switch -> AiMesh node -> Router (it's all wired, no WiFi backhaul for the AiMesh nodes)

In the above scenario if I tag the wired client's port at the managed switch with VLAN ID 53 and leave the client set for DHCP is it going to get a proper 192.168.53.x address from the VLAN DHCP server on the main router? There's also the possibility of having the AiMesh node connected to the managed switch and having the cable coming out of the wall that leads down to the main router connected to the managed switch so the wired client traffic isn't passing through the AiMesh node to get to the main router.

 

[bennor]

May or may not help answer your question; but if you haven't seen it already, Asus has a support document on how to setup VLAN. May help one to understand how setup VLAN on supported routers.

[Wireless Router] What is VLAN and how to setup in ASUS Wireless Router? | Official Support | ASUS Global

PS: If you haven't done so already, use the forum search feature to find the several past discussions on using managed switches with the Asus VLAN feature.
https://www.snbforums.com/search/14...t&c[child_nodes]=1&c[nodes][0]=37&o=relevance

 

[Seth Harman]

May or may not help answer your question; but if you haven't seen it already, Asus has a support document on how to setup VLAN. May help one to understand how setup VLAN on supported routers.

[Wireless Router] What is VLAN and how to setup in ASUS Wireless Router? | Official Support | ASUS Global

PS: If you haven't done so already, use the forum search feature to find the several past discussions on using managed switches with the Asus VLAN feature.
https://www.snbforums.com/search/14...t&c[child_nodes]=1&c[nodes][0]=37&o=relevance

Thanks for the response. Regarding the first link you posted I've visited it already prior to asking my question and it doesn't really address my question since it only talks about creating the VLAN on the main router and how to limit the types of traffic allowed across certain LAN ports on the main router and says nothing about how DHCP addresses within the VLAN are handed out. I've also read several posts on here about VLANs/Guest Network Pro and I couldn't find one that addressed my scenario, either, but if you happen to know of a specific thread that does I'd appreciate a link.

 

[bennor]

It may come down to which method of VLAN creation you use and how you configure that VLAN. If you use the Guest Network Pro Profile method to create a VLAN you should, depending on the Profile used, have an option called "Use same subnet as main network", that when enabled will pull the DHCP IP address from the main LAN DHCP IP address subnet pool. If "Use same subnet as main network" option is disabled, the user should have an option to choose the LAN IP subnet (it defaults to using x.x.52.1 for the first Profile, 53 for the second Profile and so on) that is used by the Guest Network Pro Profile.

If one uses the LAN > VLAN page to create a VLAN it appears that method just creates the VLAN but may not include DHCP. In the Asus-Merlin beta 3006 firmware the LAN > VLAN page states the following: "VLAN profile here refers to create a VLAN only network. If you want to create VLAN with DHCP, please go to Guest Network Pro".

 

[Seth Harman]

As outlined in my original post I used Guest Network Pro to create the VLAN with ID 53 and I do have DHCP enabled for that VLAN which is why I mentioned an address space of 192.168.53.x. What's unclear to me (and I haven't been able to find any posts that address this) is if the DHCP server can talk to any wired clients tagged with VLAN ID 53 and assign them DHCP addresses from that 53.x IP block. From what I've read it SHOULD work but I don't currently have a way to test this.

One thing I have noticed that's also a bit confusing is in the GUI where you can manually assign IP addresses based on MAC for that VLAN it allows you to populate from the full client list of addresses currently connected to the router, i.e. anything already connected to the main router that got an IP from the main router DHCP server can be added to the list to get an IP address from the VLAN DHCP server. But if you do this the client you selected doesn't seem to actually get a DHCP address from the VLAN DHCP server. Now, granted, this is from my limited testing on a wired client that isn't currently being VLAN tagged so maybe doing so will resolve that.

 

[Seth Harman]

UPDATE: I have a laptop that allows me to manually set a VLAN ID for the Ethernet adapter. After setting it to 53 I tested two scenarios: connecting an Ethernet cable from the laptop to one of the LAN ports on the main router, and connecting an Ethernet cable from the laptop to a LAN port on an unmanaged switch connected to one of the LAN ports on the main router. In both cases the laptop received an IP address from the DHCP server associated with the Guest Network Pro VLAN I created with an ID of 53 so I guess that answers the question of whether or not Guest Network Pro works properly with wired clients anywhere on the network that have been VLAN tagged.

UPDATE 2: I spoke too soon. If I set the VLAN ID on my laptop directly to 53 it can connect to the Guest Network Pro VLAN and get an DHCP address. If I leave the VLAN ID on the laptop as default and set the port on the managed switch it connects to tag traffic as VLAN ID 53 it does not work. I'm very confused now.

UPDATE 3: It's all working now, it was a perfect storm of my relative inexperience with VLANs and some absolutely awful user guide instructions that cover the managed switches that I purchased that was leading me to configure the switches incorrectly.