Problem setting IP address to 192.168.213.100

[rsg]

Hi,

I am working with the PK70, and want to set its IP address to 192.168.213.100/24 (i.e. netmask 255.255.255.0). When I do it, my app experiences a partial failure. It communicates in a variety of ways, some of which continue to work, while others don't.

1. My app starts up a TCP/IP server, which continues to function normally.
2. My app uses SysLog() to broadcast status messages, which works.
3. My app starts sending messages in UDP packets to port 999, which fails - Wireshark and my client apps see none of these.

If I change back to 192.168.1.100, it works as normal.

Are there any IP Address restrictions that I am unaware of? (I'm using NBEclipse 2.6.5)

Any ideas?

[dciliske]

What's your computer's IP address? What's it's netmask? What sort of IP stack offloading do you have enabled on your network card?

I'm 99.99999...% certain that this is an issue with your computer's ip and netmask settings somehow.

-Dan

[rsg]

Hi Dan,

My computer's address is 192.168.213.55, netmask 255.255.255.0. I don't know anything about "stack offloading".

The system works fully when I set the PK70 to 192.168.1.100 or 192.168.1.61, but it doesn't work with 192.168.2.xxx or 192.168.213.xxx.

[rsg]

And of course, when I'm changing the third number on the Netburner, I do the same on my computer and our router.

[rsg]

Wait - Stupid programming mistake - I had a hardcoded IP address in that (very old) portion of code. Sorry about that!

Thanks.

[dciliske]

Stack offloading is where things like netmask discrimination and ip checksum validation are offloaded from the OS's IP stack and into the interface card itself. While this improves performance for the main system, it also means that the system cannot be fully promiscuous. Although I haven't yet encountered a card dumb enough to cause this issue, I also know our system, and that was one of those "can't be"s.

Glad you found it was a hardcode deeper down. I myself fell for that while developing the WIFI driver.

-Dan