GL-MT3000 WAN port knocking internet off to the entire switch

Technical Support for Routers
1

Hello,

I have a weird problem with probably a simple solution which now excapes me, please bear with me:

From the internet to my desk, this is the configuration:

ROUTER/MODEM Asus (IP family 192.168.1.x)

managed switch Linksys GS1900-16 (default config, no subnet or anything that is not default); dozens of PC's and devices work attached to any port of this router

secondary unmanaged switch upstairs (tried Zyxel GS1005HP or Netgear GS305P, no difference). There is internet at this switch, and any PC or device that I connect directly to this second switch has internet.

Now, I have another PC that has disabled Wifi, and needs to be behind the VPN of the MT3000 (reason why I bought it). Since the PC has disabled Wifi, I connect it via wire to the LAN port of the MT3000 (IP family 192.168.8.x).

Now I know that I could have the MT3000 to connect to the home Wifi, but it's kind of weak and I prefer a wired connection for performance. The LAN port being already used, I can only use the WAN for this, and from the instruction it seems to be the correct approach.

But here comes the problem: when I connect the MT-3000 to my second switch, via WAN port, every device connected to the switch (and the MT3000) loses the internet ... it goes away. The lights of the switch remaing blinking green, but no internet. Reboot the switch, it may work for a while and then the internet goes away again.

Now the weirdest part: the internet does not go away right away: it may work for a minute, one hour, or even an entire day (work meetings, etc)! But inevitably goes away. And when it does, and I unplug the MT3000, the internet comes back immediately. It's very repeatable, so it's something that has to do with the WAN port of the MT3000 connected to the ports of this second switch.

I tried two different switch brands, but it's exactly the same.

When I eliminate the second switch, connecting the WAN of the MT3000 directly to the main switch, the MT3000 connects and all the other devices attached to the main switch continue to work.

So it seems really like the MT3000 does not like to be connected to the second switch, and when it looses the connection, it knocks off all the other devices of the second switch (but not the main switch)
Has anyone experiened something like this? What is the WAN port for, if not to connect to an existing LAN?

2

Hello,

May I know if the MT3000 2.5G WAN port is as WAN?

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When the MT3000 2.5G WAN port connected to the second switch, if the WAN port obtain the IP address (via DHCP)?

Theoretically, as long as the 2.5G WAN port of MT3000 is in WAN mode, there will be no exceptions when connecting to the second switch, and not causing problems with other devices in second switch, unless it is in LAN mode, there is a DHCP server conflict. If the WAN does have abnormal, it is also MT3000 itself cannot access Internet, and it will not affect the second switch.

4

Hi,

Yes it was setup as WAN.
The good news is that I think I found out what it was, and I think it was related to power supply: I was not using the supplied powerblock, but a usb A to C cord coming from a 10yo wall outlet that was not supplying enough power, I think.
When I switched to the original power supply, the problem went away! Already a couple days working with no issues.
Now, as to what would technically cause the entire second switch to flip out, I am not sure, but it may have to do with the switch being PoE: perhaps it detected fluctations or transients in the power and went turning PoE on or off, I am not sure.

But it was definetly a case of bad power supply, that I can easily reproduce, and now went away with the original power block.

Thanks for you comments!

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