Problem with 2 NAT boxes behind a router

I have a setup where I have multiple static IP addresses. I want to put two NAT boxes behind a supplied siemens router. One box is a webonramp, the other is a linksys.

The linksys will have my ftp server behind it, the Webonramp will have my other computers behind it. Both boxes are NAT enabled each with different subnets.

The good news is that people can ftp into the ftp site from the internet.

The problem is that I can not ftp to the ftp site from my other subnet.

This used to work when I had both boxes plugged into a Netopia box (NAT, DHCP, etc all turned off). This makes me think that it is the router that is the problem.

Now that I am behind the Siemens box, I have no access to the settings. The ISP assures me that it is "wide open."

The real problem here is that now my ISP is telling me that this configuration CAN NOT work, EVER!!! I am floored. It used to work! Is this really a problem with the NAT setup? I find that really hard to believe.

Does anybody have experience with the Siemens se5940? Is this a deficiency with that router?

What is the problem here?

Any help at all is appreciated.



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This is a TCP/IP question, not at all an ethernet question.

While some people here might know the answer, comp.protocols.tcp-ip is a better choice.

To me it seems like it should work if the siemens router does what routers are supposed to do.

Try the tcp-ip group and see if you get more replies.

-- glen

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glen herrmannsfeldt


Thanks for the pointer.

It's off to comp.protocols.tcp-ip for me.


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Are you specifying the "WAN" IP address of the Linksys router as your FTP target from clients on the "LAN" side of the Webonramp box?

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