VLAN Tagging thru a unmanaged switch

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Would an unmanaged switch in a path of a trunk line from a managed switch pass or strip the included VLAN ID inserts?
My remote switch port coded as trunk line doesn’t work with a passive coupler in series. I plugged in a switch just to watch the leds and it started working. Could be port coding , connector terminations or signal strength. More research but thought I’d ask .
Thanks
 

looktall

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The definitive answer to your question is "maybe".

Edit: if you're lucky an unmanaged switch will just pass the tags. Others might strip them or drop the packets entirely.
It really depends on the switch.

Basically suck it and see.
 
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Ri22o

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Bob's your Uncle
Robert's your father's brother.


I have my Ubiquiti APs using VLAN tagging for my wireless IoT items. They come into a managed switch, but I am using it only for the POE and no management other than naming the ports. This passes to my TP-Link unmanaged rack switch and then to my router. I have no issues with it keeping the tag.

You can see the Netgear switch patched to the patch panels to go to the APs and then the yellow patch cable connecting it to the rack mount switch.

2023-07-05_10-46-42_650.jpeg
 

DG99

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In general you should never send VLAN-tagged frames through unmanaged switches, there is no value in doing so. If you do, and the switch faithfully preserves 802.1q, then treat the unmanaged switch as if every port is a trunk port without any VLAN restrictions. Which means all paths out should lead to trunk ports of VLAN-aware switches/devices. Also any traffic can be captured from vlan on unmanaged switch. Any broadcast packets from your main network will pass to all vlans. Will work for home, do not use in business setting.
 
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I’ll try wireshark. Some missed the story. I have a coupler to extend the cable on a trunk path for a remote VLAN. and it didn’t work. I put an unused switch in the path cause it was close and to watch the leds. It started to work. .?? I was wondering if it stripped the included Vladimir ,etc.
VLAN s are new for me. I may strip it all out as the slower processing of L3 is causing missed frames.
This is a home situation. Thanks
 

Ri22o

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In general you should never send VLAN-tagged frames through unmanaged switches, there is no value in doing so. If you do, and the switch faithfully preserves 802.1q, then treat the unmanaged switch as if every port is a trunk port without any VLAN restrictions. Which means all paths out should lead to trunk ports of VLAN-aware switches/devices. Also any traffic can be captured from vlan on unmanaged switch. Any broadcast packets from your main network will pass to all vlans. Will work for home, do not use in business setting.
Any thoughts on how to remedy my set up?

Unifi AP has 3 SSIDs. Main, Guest, and IoT. Guest is handled internally to the AP as a VLAN, so it's not an issue. This leaves the Main .0.XX and the IoT VLAN ID 20.

How do I forward the IoT VLAN ID to a specific port on my Netgear switch and preserve the Main? I can figure out how to handle things at the router, but I can't wrap my head around how to get these segregated in the managed switch.
 
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This question arose because an unmanaged switch was added to the trunk line just to watch /read the led response and adding it to a failed line, made it work. So my above question.

I tried wireshark, that is interesting... As it turned out it was a wet line and connection, that apparently got a boast from an added switch that wouldn't work without the switch ,,, because of all the rain this winter. re-established the circuit on a MoAC circuit and planning to replace with a fiber line in the spring. Under ground cables are troublesome when they are constantly wet.
 
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