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Forum Discussion
Jeremy__
Oct 17, 2019Aspirant
VLAN tagging not working on GS750E
Hi, I am currently configuring some VLAN on a GS750E switch (48 ports, managed). Firmware version is the last : 1.1.0.4 I tried to setup a single tagged VLAN, but the tags are lost on every ...
- Oct 18, 2019
Looks like a bug to me. Afraid, the few GS750E are operating with just a tagged trunk/uplink and untagged ports (to multiple VLAN), no issues that far (and can't change the customer environment for testing) I'm afraid. Please get in touch with the Netgear support via https://my.netgear.com/ - these switches are coming with a limited lifetime warrant and lifetime chat support.
Jeremy__
Oct 18, 2019Aspirant
Hi,
First ,thank you very much for your answer.
I used the PVID and only tagged 1 VLAN to demonstrate the issue, in the simplest configuration possible.
I do intend to use multiple tagged VLAN on some ports, and to untag most of them in a default VLAN.
But right know, I can't make 2 single host communicate on tagged ports ...
Both machines are indeed configured to handle tagged traffic, and as proof of that :
The machine 1 send its ARP requests tagged with VLAN 20.
The machine 2 takes this tagged ARP request, and answers a with tagged VLAN 20 packet.
That prooves that both my machines are OK with tagged VLAN 20 traffic.
My issue with the switch is :
the tagged ARP answer he received from the Machine 2 is transmitted to the Machine 1 (good port) but the tag is removed.
Even when the source port is PVID 20 (so I know the switch either understood the tag, or default it to VLAN 20), and the destination port is VLAN 20 tagged.
I tried to force it to tag all packets, by making sure that all ports are only in VLAN 20, all ports are tagged, and even if incoming packets are not tagged, they are in the correct VLAN (PVID). In this configuration, as all ports are tagged, every single packet emitted by the switch should be tagged, right ?
The tags works with broadcased packets (ARP request) but not with single host one (ARP reply).
That's what I dont understand. Same VLAN, same ports, both incoming packets tagged, and yet different behaviour ?
Best regards, Jeremy
schumaku
Oct 18, 2019Guru - Experienced User
Looks like a bug to me. Afraid, the few GS750E are operating with just a tagged trunk/uplink and untagged ports (to multiple VLAN), no issues that far (and can't change the customer environment for testing) I'm afraid. Please get in touch with the Netgear support via https://my.netgear.com/ - these switches are coming with a limited lifetime warrant and lifetime chat support.
- Jeremy__Oct 18, 2019Aspirant
So I did a few more tests with scapy.
It seems there are undocumented, unchecked limitation on the switch :
There can be only one tagged port, the others must be untagged and take advantage of the PVID.
I'm gonna contact the support about this, but if this is the case, it should be documented, advertised, and checked by the administration interface ...
Thank you again for your time and your answers !
Best regards
- schumakuOct 18, 2019Guru - Experienced User
Jeremy__ wrote:It seems there are undocumented, unchecked limitation on the switch :
There can be only one tagged port, the others must be untagged and take advantage of the PVID.
We operate multiple tagged ports in a daisy chain trunk config, that far it isn't limited.
Ok, looking what support will come to ... don't forget to add a link to this thread, this should allow the short cut to L2.
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