On Sat, 28 May 2005, Jim Cornette wrote:
Setting the netmask for the computer to 255.255.0.0 allows communication between a computer with addresses in the 192.168.127.x and with devices in the 192.168.2xx.x range. The problem I am experiencing is intermittent dropout of "smart devices" that also have settings for masking and are set to 192.168.127.xx with a mask of 255.255.255.0. The computer ethernet address is set to 192.168.217.14.
If the netmask is wrong on those smart devices, they will need to route through their default gateway to return traffic to you.
That said, I've seen (and it is possible for these smart devices you're referring to) to cache the IP/ARP mapping seen from the first packets that your computer sends to the smart devices. That would explain why this appears to work. But ARP cache entries will expire. When they are gone, the smart devices will try to send the packet according to normal IP routing rules: i.e. if not in the same subnet, must route through default gateway. If you do not have a default gateway for them, the packet is lost.
This seems to describe the problem encountered. I believe a default gateway is specified, but there is no gateway available with these smart devices.
Anyway, could the intermittent dropout with communication be caused by the masking on the smart device not ranging with the IP of the computer or would the broader setting for the computer be enough to not cause a loss of connectivity.
You should really try to get the netmask set correctly. You cannot depend on a "netmask trick" done on just one end to make it work reliably for both ends of a communication.
I'll see what setting the smart device masking to the wider setting to see if the dropouts cease.
Thanks for the answer and Scott for his answer as well.
Jim
Regards,
.lzs -- http://zitseng.com/
-- Some Windows were made to be broken.
