RUTXR1 as mobile passthrough as well as AP

NETWORKING SOLUTIONS
1

I have recently replaced the routing function in my RUTXR1 with a more capable mikrotik - with starlink as the main WAN.
The RUTXR1 mobile data connection is now available to provide a second WAN (ie backup) for the mikrotik and a Wifi access point - with the routing being done by the mikrotik.

Is this possible with the RUTXR1 and what are the requirements (one physical ethernet link, or two?).

My thoughts:

  • Mobile passthrough mode - allows RMS access.
  • The mikotik gets the mobile WAN IP passed through from the RUT - advice on configuring RUT? LAN1 of RUT is connected to WAN2 on mikrotik.
  • The access point is somehow bridged to the mikrotik - this is the main part I’m unsure about is if this requires yet another physical ethernet cable or not.

Also, I operate ZeroTier on both devices. As soon as I set mobile passthrough on RUT, Zerotier_RUT goes offline. Can anyone advise this also?

3

Hello,

In the Mobile passthrough mode, RUTXR1 assigns the mobile WAN IP directly to the MikroTik’s WAN2 interface.
You’ll need to ensure the RUTXR1 is set to Mobile Passthrough Mode under Network → WAN → Edit the interface → Mode → Passthrough.
Since this mode disables NAT and routing on the RUTXR1, ZeroTier on the RUTXR1 will go offline because it no longer has a routable IP (only the MikroTik gets an IP).

If you need the RUTXR1 to provide Wi-Fi as part of the MikroTik’s network, you’ll likely need a second cable:

  • Cable 1: RUTXR1 LAN1 → MikroTik WAN2 (for mobile passthrough).
  • Cable 2: RUTXR1 LAN2 → MikroTik LAN (to bridge Wi-Fi).

If you want devices on the RUTXR1 Wi-Fi to be part of the MikroTik network:

Configure the LAN port (LAN2) on the RUTXR1 as a bridge.
Connect LAN2 to a MikroTik LAN port.
Set up the Wi-Fi on the RUTXR1 as a bridged AP, forwarding traffic to the MikroTik LAN.
Ensure DHCP is disabled on the RUTXR1 so the MikroTik handles all IP assignments.

The above can be achieved by creating a new interface, configuring it by disabling DHCP and enabling Bridged interfaces, you’ll also have to select the networks to bridge between in the settings seen below:

image
image907×406 17.3 KB

Regarding the ZeroTier issue, when Mobile Passthrough is enabled, the RUTXR1 no longer has an IP (since it is passing it to the MikroTik).

Let me know how it goes,
M.

4

Thanks so much - this is the reply detail I was hoping for (mostly)!

Got it

  • two cables required for AP and WAN functions.
  • zerotier can’t function in passthrough mode (though I have seen other topics here that say the lan continues to operate in passthrough and bridge modes - see Differences with Mobile Modes (NAT, Bridge, Passthrough) - #6 by Daumantas).
  • RMS remote access should still function in passthrough mode? I’d really like to still be able to access webUI of teltonika.

eth0 and eth1
So that I make sure I understand the logic, when you say

The above can be achieved by creating a new interface, configuring it by disabling DHCP and enabling Bridged interfaces , you’ll also have to select the networks to bridge between in the settings seen below:

and your screenshot shows eth0 & eth1 selected, does this mean that on the RUT, we are bridging the mobile port (eth0) and the wifi AP port (eth1), or bridging the lan to those ports? This seems like strange logic to me, since the eth0 carries the singular passthrough IP, while the eth1 port carries the AP clients to the mikrotik LAN, with very different subnets. I would have thought that eth0 would be excluded here.

I’m also wondering, with that interface created (under LAN?) does any Wireless SSIDs configured just automatically associate to any LAN interface, unless bridged - as you have specified?