Connection with ISP dropping when using VLAN tagging with DHCP (IPoE)

[tumma72]

Hi everyone,

 I have stumbled across a new issue recently, not even sure how this happened because till few days ago everything was working smoothly and effectively. I am a happy owner of 2 5G WiFi Mesh System, AX4200 (NBK752) which I use in two different locations, I have chose them because of the 5G Mobile network backup which allows me to always connect from remote to both locations and check security warnings and other things. In both location I am having contracts with ISPs who provide Fiber Optic connections (up to 1Gbit/s) by using an IPoE approach with VLAN tagging. The ISPs are different, but on one side I have the following working setup:

- Choose ISP with authentication, then choose the option with DHCP, then VLAN tagging on ID 832 and Mobile 5G configured as backup

Till several days ago the same setup worked also with the other provider. Notice that both providers also share their telephony and IPTV on the same connection, but on other VLAN tags. What happens now in the second location is that, because I do not need authentication as the password is inside the ONT modem, I have to chose the option without authentication, then the VLAN tagging on ID 835. If I do that as a result the standard "internet" VLAN option is automatically selected, and when I go back to the connection settings, the connection has switched to DHCP with Authentication, and is preselecting the "ORANGE DHCP France" profile. No matter what I do the two things seem to be connected, I have been successful in setting the VLAN temporarily while Testing the connection without authentication, then the router connects for a couple of seconds (sometimes even 30-40 seconds) and then the connection drops with the IP on the WAN reset to 0.0.0.0.

If I try to connect again, doesn't work, and if I go and check in the connection settings one of the following 2 things has happened:

1. The connection is set back to DHCP with authentication, and the ORANGE France profile, which doesn't work because I do not have username and passwords to supply

2. The connection is still set on DHCP without authentication, but the VLAN settings are gone, actually the VLAN Bridge option is unchecked entirely

I have tried multiple factory resets, as well as re-flashing the latest version of the firmware (V4.6.5.11_1.5.50) a couple of times, nothing helped. The satellite is also on the latest version of the firmware which is V4.6.5.14

Thanks for any help or advice you can provide

Ciao

ANdreaT

P.S.: The temporary solution is to leave the ORBI in AP mode, and use the internet provider router instead... but of course I am losing the option to have a 5G mobile backup, which defeats the purpose of having an NBK752 🙂

[tumma72]

I have made further tests to understand if it is a problem with the ISP, and apparently it isn't... if I connect my laptop straight to the ONT using an ethernet cable, configured to obtain the DHCP address using the VLAN tagging, it works like a charm. It connects and gets the public IP address directly shared to the interface, as expected. The IP it isn't revoked and the lease is for 24h. If I attach the ethernet cable back to the ORBI WAN port, it connects as a first attempt, but then a couple of seconds later, resets the IP to 0.0.0.0 and shifts towards the 5G mobile connection.

It seems to be a misbehavior of the configuration at this point, does anyway have encountered a similar problem? If so did you manage to solve it? Any idea about what else I could be trying?

Thanks

ANdreaT