my R510 AP cannot used on the default VLAN but ok on other VLANs, how can i fix that?

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my R510 AP cannot used on the default  VLAN but ok on other VLANs, how can i fix that?

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simon wong

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Posted 2 weeks ago

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Paul McGuire

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Untag the VLAN on that switch port or change the VLAN on the SSID to VLAN 1
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Victor Cenac

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That's most likely a switch config issue. On a trunked port, plug a laptop in. Does it work?
On a trunked port you should be able to set a default or native VLAN that is not tagged. And that is what the AP could use. Test with the laptop.
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simon wong

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The ssid set to run on VLAN1 (default) & the switch port untagged on VLAN1, it does not work.

But change the switch port to other VLAN then it works, strange!!
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Victor Cenac

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If the switch interface is set to a single VLAN (access mode), then it really does not matter what VLAN is set on the port, it will be untagged. It is exactly the same for the AP.
If VLAN 1 doesn't work, but VLAN 20 does, then the VLAN1 is not setup properly on the switch, or DHCP doesn't work on it, etc. Again, test it with a laptop.

If the port is set as trunk (802.1q), then multiple VLANs are set on the interface, usually one of them as default, or untagged, usually VLAN 1. When you plug a laptop into it, the laptop will use untagged traffic, VLAN 1. If it works, then the switch is good. The AP has a setting for what VLAN to use for management and what to use for different SSIDs. The management has to be set to VLAN 1. You can verify, by plugging the AP directly into a laptop nic. If you are running Windows, turn on Internet sharing on its WIFI card. This will turn on a DHC{ server in the laptop and the AP will be offered an IP. Verify that you can reach the AP. If yes, then your AP is set correctly to use untagged traffic for management.

But from what you are saying, it looks like the switch port is set to access mode with a single VLAN on it. The AP has no way of knowing what VLAN is set on the switch interface, since the traffic is untagged.
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simon wong

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Thx for yr reply, Victor.
I think both the switch & the specific port are functioning. I plugged in a laptop as suggested. It got an IP from VLAN1 if I configured the port on VLAN1, got IP from VLAN2 if configured as VLAN2. Internet connection works perfectly.

The AP ssid is on VLAN1, if switch port on VLAN1 it does not work, but if on VLAN2, it works!!

Then if both AP & port on VLAN2, it does not work either.

Really can't explain!!


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Victor Cenac

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Can we get the switch config for that port?
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simon wong

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port 28
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simon wong

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port 28
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Victor Cenac

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Great! The VLAN 2 assigned to interface 28 is not tagged. Thus it really doesn't matter what VLAN that is. There are no tags. At this point, the AP will probably work set on VLAN 1, if that's set as untagged on it. When you switch the AP to VLAN 2, it thinks it has to tag the traffic with VLAN 2... tags, or vlan-id. But the switch is only accepted untagged traffic, therefore the packets from the AP are dropped.
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simon wong

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The AP is on VLAN1 !!!
The only combination that works is AP on VLAN1, while the port 28 on other VLAN (2,3, ..) but 1.
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simon wong

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it works but we dont want to assign IPs under VLAN2 to the mobile devices accessing this AP. We want to assign IPs under VLAN1.