Question

With an RUT240 modem configured in bridge mode, my firewall is configured to use a static IP address provided by my ISP (subnet size is /30). As an example, the firewall interface IP is set to 1.1.1.1 and the gateway is 1.1.1.2. The problem is that when data is sent to the gateway (10.1.1.2), the RUT240 appears to be responding instead of the actual gateway.

If I ping 1.1.1.2, the RUT240 replies. If I access http://1.1.1.2, the RUT240 web interface is shown.

Note that the IP address for the LAN interface on the RUT240 is not the same as the IP address provided from the ISP. Obviously, the IP provided by the ISP is public, and the LAN IP is within the private network class.

The modem is running firmware version: RUT2XX_R_00.01.11.3

This is not the expected behaviour! Can anyone from Teltonika provide some help?

Answer 1

Hello,

In this scenario RUT240 acts as a gateway and it is normal that it responds to you when you try reaching 1.1.1.2

You should be able to reach your firewall via ip 1.1.1.1 (Your public IP)

Comments

Apologies for the late response —

This behaviour does not make sense to me. For example, if my ISP had services hosted on 1.1.1.1, then it would be impossible to access them, because the RUT240 would be responding instead of the ISP's equipment.

Is there some way around this?

---

Hello? No response?

---

Hello,

Sorry for the late reply.

Regarding services on ISP gateway router, do you have any services in mind that you want to use? Because I am not sure I have ever seen an ISP gateway router with available services for customers.

Also, could you see what gateway you get from ISP without using bridge mode? You can connect to the router via SSH and execute ifconfig to see IP addressing on interfaces

Then compare it to gateway you get on your bridged device after enabling bridge mode on the router. Are they the same?

---

Hi —

Yes, you're right, it is not common for ISPs to host services on the gateway IP allocated to the customer; however, it is possible, and it is still important that when sending data to the ISP's gateway (for example, diagnostic purposes with ICMP echo), that it actually reaches the ISP's equipment. I feel like the current implementation of bridge mode on the RUT240 exhibits bad practices. I have an RUT950 (also in bridge mode), and it works exactly as expected in these circumstances. Why can't the RUT240 function in the same way?

I did check, and, yes, the IP address and gateway IP assigned to the RUT240's WAN interface (while not in bridge mode) is the same as what is assigned to my equipment when in bridge mode. This is exactly what I would expect to see.