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NI 9792 with Sierra Wireless Raven XE Modem/NAT Router - Port Forwarding Issues

Dear Members,

 

I have a Wireless Sensor Network (WSN) system made up of a NI 9792 RT Gateway connected to a Sierra Wireless Raven XE HSPA World Edition (H2295E-W). The system architecture is shown in the attached word document.

 

We have a Web UI developed and this runs on the Application Server port 8080. It can be viewed and parameters changed when the Gateway is connected directly to a desktop PC via Eth0 (ethernet port 1). 

 

We would like to be able to access the Web UI application remotely, so that we can make changes to devices in the field from the office. 

 

I know that this process must be done through port forwarding, according to the NI KB: http://digital.ni.com/public.nsf/allkb/FE64994F19D12273862579AB008001D1

 

I also know that port forwarding is possible with the Sierra Wireless Raven XE modem that we have in the system. 

 

We currently have a Three UK 3G Fixed Public IP SIM card installed in the modem so that the IP address can be found via the internet and requests made. 

 

The Sierra Wireless allows Port Forwarding rules to be set up so that requests for particular public ports made to the modem can be passed on. However, I know believe that simple port forwarding in the modem will not allow the requests to be passed towards the Application Server on the Gateway (refer back to system architecture). 

 

I believe that Double Port Forwarding is required where we have the following situation:

 

- Remote PC makes request over internet by typing in the IP address of the 3G Fixed Public IP SIM [This can be considered the external IP of the MODEM]

- This then passes the request directly to modem's device IP - 192.168.13.31 [This can be considered the internal IP of the MODEM]

 

Port Forwarding Rules are then enforced and any requests made on public ports should be routed to the appropriate Host IPs & their associated private ports. These then arrive via direct ethernet connection to Eth1 (Port 2) on the Gateway, which has IP address of 192.168.13.100.

 

Now. The issue is this. The Web UI application, which is hosted on the Application Server, accessible on port 8080, has the IP address of 192.168.0.101 and is in Eth0 (Port 1) on the Gateway. This presents two problems:

  1. We have a different subnet for each ethernet port on the gateway
  2. How do we pass on the request from Eth1 (which is directly connected to the modem) to Eth0 which isn't and has a different subnet/IP address?

 

This is why I believe double port forwarding (see URL below) is required but I am unsure how the two ethernet ports communicate on the gateway. I am aware that I may be required to make the connected port (Eth1) as a DMZ IP, so that any unsolicited requests made to 192.168.13.100 are passed on, but this still does not get around how to communicate between the two ethernet ports. 

 

http://portforward.com/help/doublerouterportforwarding.htm

 

The other option is to somehow make the Gateway a WAP or ethernet switch so that the request can be passed through directly. Is it correct to assume that the Gateway is acting as a second router to the modem and therefore we have two routers connected, causing a block to any port forwarding process. 

 

Any clarification on how the two ethernet ports on the NI 9792 are linked and how they communicate would be greatly appreciated.

 

Should you required any further information, please contact me.

 

Many thanks,

 

Dom.C

 

 

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Hey Dom,

 

The Application Server port should responds on the same port on either network card. As long as the subnets are mutually exclusive then what you are saying is possible. 

 

There shouldn't be a need for double port forwarding. Worse comes to worse we'd recommend putting a switch between all three devices to simiplify your networking. 

I believe your subnets are setup incorrectly. Vxworks is pretty simple in how it handles networks it can't handle network cards with too similar of ip and subnets.

 

The easiet way to handle your networks is to use to distinct ip address ranges. 

 

Configure the internal ip of the modem to 192.168.13.129 with a subnet of 255.255.255.0

Configure Eth 1 of the WSN gateway to be 192.168.13.130 with a subnet of 255.255.255.0

Configure Eth 0 of WSN gateway to 192.168.14.1 with a subnet of 255.255.255.0

Configure PC to 192.168.14.2 with a subnet of 255.255.255.0

 

You could also set the subnets to say 255.255.255.128 so 192.168.13.129 and 129.168.13.1 are on seperate subnets because the 128 is a network split point. Anything greater than 128 can see and talk to each other but can't talk to anything below it, without a router.

Kyle Hartley
Senior Embedded Software Engineer

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Hi Kyle,

 

Many thanks for your reply.

 

Apologies for not getting back to you for a little while. I am only available to work on the current project every Tuesday.

 

I appreciate your help and suggestions.

 

I have tried implementing both options in regards to the IPs/subnets that you mentioned but unfortunately neither option has worked for me.

 

Perhaps I wasn't explicit enough in my previous post regarding what I am trying to do.

 

I am making a request from a PC in my office (IP address 81.13.1😎 to the 3G Fixed IP SIM within the modem (IP 5.xxx.xxx.xxx). This is being done through Google Chrome web browser by typing 5.xxx.xxx.xxx:8080/Gateway/Index/html.

 

The WSN system is in our laboratory, connected to a different desktop PC (the one mentioned in the WSN System Architecture document). Currently, we are able to view the Web UI when entering the IP address (192.168.14.1:8080/Gateway/Index/html - based on your suggestion) of Eth0 on the WSN gateway, when directly connected via ethernet to the PC. We want to have this accessibility to a remote system at a clients office. The WSN we have here is a demonstration one where we play around with settings and improve code etc. 

 

Furthermore, when in the NI Web-Based Configuration, there is also an IP address related to the Gateway itself - this was originally 192.168.0.31, then changed (based on your suggestions) to 192.168.14.31 and then to 192.168.13.31. Do you think this IP address may have something to do with the process not working? I am not currently making any requests/addressing this IP (see attached image regarding the NI Web-Based Configuration).

 

On the modem's settings, I have set up a port forwarding rule: Public Start Port 8080, Public End Port 8080 [this features allows for entering a range of ports if desired], IP address 192.168.14.1, Private Port = 8080. (see attached images regarding the modem settings)

 

The other potential issues I believe could be stopping the process from working are:

 

- A loopback error on my modem - would you know how to identify if this is the problem?

- A firewall blocking requests within the office LAN - I don't believe this is actually happening but I can easily disable firewalls on my PC to ensure this isn't a problem.

 

In addition, would Port Triggering be a requirement at all?

 

I am unsure in regards to how to proceed from here. Further suggestions/advice would be really appreciated. I am only able to work on this project this afternoon and next Tuesday before we no longer have the 3G Fixed IP SIM. I understand this may not be a direct NI related issue but something to do with the gateway is not allowing the process to work. 

 

Once again, many thanks for your assitance in this matter.

 

If you require further information, please let me know.

 

Regards,

 

Dom.C

 

 

 

 

 

 

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Dom,

 

In your screenshot Eth 0 is setup as 192.168.14.1 which is the ip you are looking to forward through your cell modem. Portforwarding only works if the device port on the network has the same ip address.


I've modified your cast to make sure we are setting all the values correctly.

 

Kyle Hartley
Senior Embedded Software Engineer

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Dear Kyle/Community,

 

Apologies for the extremely delayed reply to your last post. I haven't been in the office for a few weeks. 

 

I managed to fix the port-forwarding issue by changing the following parameters:

 

- In the NI-Web Based Configuration tool, I changed Eth0 (primary ethernet port) to have a subnet of 13, so it now has IP address 192.168.13.101. In addition, for the option 'Gateway', this needed to have the same IP address as that of the Ethernet port of the modem; 192.168.13.31. This was the KEY to getting the port forwarding process to work. It is critical that the NI 9792 RT Gateway knows to look back at the modem's IP address. If this is anything different, the process does not work. 

 

- In our modem, I set up two port-forwarding rules, one for the Web UI Application (which runs on port 8080) and one for access to the modem's software (which runs on port 9191). 

 

Therefore our NI 9792 Gateway now has both Eth0 and Eth1 with a subnet of 13, but we can remotely access our Web UI Application, as well send SMS warnings through the modem. Both of these functionalities are reliant on having a 3G Fixed Public IP SIM with both DATA and TEXT allowance. For our particular application, we contacted a very good vendor of these specialist SIMS called:

 

www.comms365.com

 

I hope this helps fellow community members who may be trying to develop an application using the NI 9792 RT Gateway and who wish to access a Web UI application remotely. 

 

Many thanks for your support on this issue, it was greatly appreciated. 

 

Kind Regards,

 

Dominic Clarke

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