Zyxel T-56 WAN Port Flapping Issue with VLAN Tagging

Thank you,
I tried these configurations on OpenWrt router (which is not EX5601 nor EX5401) and connected it directly to OdidO cable but did not work out. Internet only works if router is OdidO router with stock firmware.

So setup that works is as follows:

(INTERNET) <-----> [[ OdidO router with Original Firmware ]] ----- [[ OpenWrt ]] ------ [[ Home Network ]]

I assume the Odido device is removed while testing openwrt ?
if not, there's no need for VLAN.

this isn't really device specific, and shouldn't have been asked in this thread.

Just to clarify and share an update for others who might be planning to install OpenWrt on the EX5601 – especially those using it with an Odido connection:

In my case, the internet connection didn't work out of the box after flashing OpenWrt. but I imagine many users might keep it connected (at least initially), so I think it's useful to mention.

I do understand your point that the VLAN setup isn’t specific to the EX5601 itself, but I still believe it’s relevant to this thread. Someone browsing here might assume that OpenWrt will "just work" with their existing setup, so it's worth pointing out this potential issue.

Hopefully, this helps others avoid confusion or connectivity issues!

of course not, you're booting openwrt now.
it's like installing Linux, and complaining about your Windows settings not making it across.

you would have had the same issue with any devices running openwrt, hence not device specific.

it could, depending on the setup.
any ISP requiring VLAN or PPPoE logon will fail post install.

This what I did, I put another TP-Link with OpenWrt and also it did not work.

So, connecting EX5601 with OpenWrt or TP-Link with OpenWrt to OdidO intenet cable, both did not work.

OpenWRT is great, but it's still not a mind reader.

I rest my case.

Sounds related to

just throwing this one in there:

https://git.openwrt.org/?p=openwrt/openwrt.git;a=commit;h=f7d40365558f3426b85be35f1f2ba7d01df96dd0

kernel: mtk_eth_soc: fix tx vlan tag for llc packets

When sending llc packets with vlan tx offload, the hardware fails to
actually add the tag. Deal with this by fixing it up in software.

Fixes: https://github.com/openwrt/openwrt/issues/19916
Reported-by: Thibaut VARENE hacks@slashdirt.org
Signed-off-by: Felix Fietkau nbd@nbd.name

I assume this would only help if you were using pppoe for the internet as well as vlan though