Is there a NAT configuration example available?

[adrianjelea]

Hi,

I have set up a K70 board with both GPRS and ethernet connections up and running.

I have found some discussions about MQX beeing able to support NAT, but there is no available example.

What i need to do is when a connection on a speciffic port, ex: 80 is comming towards the gprs modem,

that connection to be forwarded to an IP over the ethernet.

Is it possible?

Thanks,

Adrian

[soledad]

Hello Adrian,

Unfortunately we don't have anything else than what is written in the MQX RTCS User's Guide.

I'm afraid we've not used NAT in any of our demos/examples.

But if you follow the code snippets in the MQX RTCS User's Guide, I think you could use it.

Please read the limitations of the MQX NAT implementation, in section 2.14.5.1 on page 37.

2.14.5.1 Limitations

Freescale MQX RTOS implementation of NAT does not support:

• IGMP and IP multicast modes

• Fragmented TCP and UDP packets

• IKE and IPsec

• SNMP

• Public DNS queries of private hosts

• H.323

• Peer-to-peer connections. Only the private host can initiate a connection to the public host.

In addition, the Freescale MQX RTOS implementation of NAT can operate only on a border router for a single private network.

Have a great day,
Sol

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[josephchen]

Hello,

     I have also encountered the same problem as Andrian. The IP checksum will be recalcutated wrong by NAT. It only works if I turn off Ethernet hardware checksum. Any solution for this?

Kind Regards,

Joseph Chen

[adrianjelea]

Thanks,

i managed to get NAT configured, but there is a problem with the IP checksum recalculation after ip address change.

the packet gets forwarded on the ethernet interface as it should, but with a wrong IP header Checksum.

so it is dropped by the receiving end.

i try to figure out what is wrong in rtcs code.

as is it is usless.

best regards,

adrian