Differences with Mobile Modes (NAT, Bridge, Passthrough)

Hello, I’m new to Teltonika and RUT products. I’m looking for details on what happens when you switch from the default NAT mode to Passthrough and Bridge modes for a mobile interface. Specifically, what additional interfaces are created and why, as well as what features and functionality become active/inactive and why. I realize that’s pretty open-ended - just hoping to get as much detail/info as possible so I/We can determine how to best utilize/configure the devices for certain applications/situations.

Thank you.


I’ll go over each of the modes and explain a little about all of them:

  • NAT mode
    This is the most commonly used mode - it handles L3 routing, as well as NAT (Network Address Translation). In this mode, managed Teltonika products can support more than one LAN client, by providing each of them with a private IP address. If you have a public IP address on your mobile interface, port forwarding can be configured to forward specific ports to LAN clients. Some people also treat NAT as another layer of security, as without manually opening the ports from the public internet, LAN clients will not be reachable.

  • Passthrough mode
    In this mode the router shares the IP address assigned by the operator with a single LAN clients. Great option in cases where the router needs to have internet access itself (for example RMS, ping reboot, monitoring, etc.).

  • Bridge mode
    The router forwards the DHCP lease from the carrier directly to the LAN client. This way the router/gateway will only act as a “bridge” between the LTE network and a wired client.

It should also be noted that in Passthrough and bridge modes the device will not be reachable. In order to reach the WebUI you’ll need to set a static IP address of the router LAN network.
More information can be found here: RUTX11 Interfaces - Teltonika Networks Wiki
Hope this helps!

Best regards,

Hello Daumantas,

Thank you for the information here. Is this the same for the NAT, Passthrough, and Bridge modes on the Gateway (TRB series) devices?

Thank you.

Can you also confirm whether or not access to the device’s onboard web-based management GUI is supported in all three modes (NAT, passthrough, and bridge)? Is this the same for both router (RUT) and gateway (TRB) devices? What about RMS support in all three modes for both router and gateway products?

Thank you.


Yes, this mode is available on all managed devices.

WebUI is only accessible when using NAT mode.

Yes, the behavior is identical.

RMS is supported on all managed devices, however, to use RMS the device needs to be in NAT or Passthrough mode. It will not work in Bridge mode as the device will not have internet access.

Best regards,

Hello, After testing functionality of the RUT240 in Passthrough mode I discovered that, while the device does indeed “share” it’s public IP with a single client (first client that’s connected), it still supports multiple clients which get assigned private IPs per the DHCP settings for the “lan” interface. Further, these additional clients are able to access the internet, suggesting that NAT is still enabled and functioning in passthrough mode… As well, I found that the device’s web management portal is still fully accessible from both it’s “lan” IP address, as well as the “mobile_bridge” IP while in passthrough mode. Lastly, I found that by configuring port forwarding on the device, I can also access the web management portal from the public IP, suggesting that the port forwarding functionality is also still active while in passthrough mode.

@Daumantas I don’t understand why you’re providing misleading information on the device functionality in passthrough mode. But if it’s possible to get a more detailed (and accurate) response on exactly which functionality/features of the RUTOS are active/inactive within the different modes this would be much appreciated. Thank you.

P.S. Why are the forum convos set to “close” so soon (2 weeks) after they’ve been opened?


Indeed, missed this part. Apologies.

At least on Windows machines, this is only the case while the route to the LAN IP of the RUT240 is still present. If the connection is reset and the routes are not added, the WebUI will not be reachable. This could be overcome by adding a route to <LAN_IP> via <mobile_interface_assigned_IP>.
The same goes for bridge mode. However, if additional clients are connected, they will receive a LAN IP (without internet connection) and will be able to access the WebUI.

To put it simply, passthrough mode operates similarly to NAT, but one of the clients will be assigned the mobile IP address. In bridge mode, only one client will receive the mobile IP address, and it will have the exclusive access to that address, without sharing the internet connection with other hosts or the router.

Best regards,

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