VMG devices bridge mode not accessible via it's management IP

Peter2

You can test it with a laptop connected to the running Modem on another Lan Port if it works both : access with the same adress of the Modem oder access over Lan4 with your new interface .

Then you have to configure your synology right to get access over your Network .

k1s

https://community.zyxel.com/en/discussion/comment/70321#Comment_70321

It's not practical to run cable from the modem to a laptop and I want to turn off the wifi from the zyxel so it doesn't interfere with the other wifi in the building. The whole point of this thread is to access the zyxel management gui via the primary lan.

Peter2

Of course this is your decision …

One thing at last - may be its better to give the new interface on Lan4 really a adress in your primary lan like 192.168.1.252 and the modem adress change to 192.168.100.1 which is a standard bridge modem adress very often . Then connect the modem Lanport to Wan port of the router and the new interface Lan4 port to a switch of your network .

Only a remark to complete this if somebody like to try this out !

k1s

So far, the best I can do is a workaround.

I've set the VMG3925-B10C to bridge mode, with an IP 192.168.5.1

In Synology router if I change the internet connection from PPPoE to manual and enter an IP address in the same subnet (102.168.5.3 in the example below), it temporarily disconnects me from the internet but allows me to reach the VMG3925-B10C configuration pages from a PC on the LAN 192.168.1.x.

When I've finished, I have to switch the internet connection back to the original PPPoE and re-connect it, like this:

I guess the reason the internet becomes disconnected is the ISP wants the broadband account username and password from somewhere and while the VMG3925-B10C is in bridge mode it doesn't tell the ISP the account username and password (even though it is stored under Networking > Broadband VDSL.

In those settings, if I change to routing mode and PPPoE (as opposed to IPoE), it allows me to enter and store the broadband account username and password, but then of course I have two routers on my network interfering with each other.

Does anyone know how I could leave the VMG3925-B10C in routing mode but effectively disable routing functions (obviously disable DHCP, but what else, that would simply pass the internet to the main [synology] router, and not involve itself in any other routing)?

k1s

I was finally able to resolve it with the help of Synology support who suggested adding a policy route.
In case anybody finds this post with a similar issue, the set-up is as follows:

Primary router is Synology RT6600ax, with default IP address 192.168.1.1

VMG3925-B10C set with an IP address for the configuration pages outside the subnet of the primary router, in my case IP 192.168.5.1 (set under Networking > Home Networking > LAN IP Setup)

VMG3925-B10C set to bridge mode, set under Networking > Broardband > VDSL > Modify (pencil icon) > Mode "Bridge". My ISP (Onestream) also requires VLAN set to 0 and 101.

In the Synology router I had to add a manual entry under the internet connection

…then switch back to PPPoE (where the broadband account username and password details are included).

Finally, I had to add a policy route like this:

Network Center > Internet > Smart WAN > Policy Route

Source IP 192.168.1.0/24

Destination IP 192.168.5.0/24

Interface: PPPoE-WAN

Now I can access the VMG3925-B10C configuration pages at 192.168.5.1 from any PC / device on the primary LAN 192.168.1.x