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How to UDP Broadcast on subnet only?

0 votes
Hi,

I am using a ConnectCore 9P 9215 with NET+OS 7.4.2.

I am have problems broadcasting on the local subnet only, using sendto() as I get an error - No such file or directory. I can broadcast to 255.255.255.255, but for a /16 prefix I can't send to the host broadcast address without an error, for example 192.168.255.255.

I have tried binding to the local IP address and port number and also setting the SO_DONTROUTE option, but these did not help.

Anyone who has had similar problems and knows a solution please let me know!

Best regards,

Dave
asked Oct 12, 2010 in NET+OS by david.lockyer New to the Community (15 points)

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4 Answers

0 votes
OK,

I think I was just confused...

255.255.255.255 is a limited broadcast, that only goes to the local subnet - good.

Where for example 192.168.255.255 (/16 CIDR prefix) would be a directed broadcast and would be routed to the destination subnet and then broadcast, provided the switch/routers don't block the directed broadcast on the way.

But why are directed broadcasts not sent and is there an option to allow them? One use of this in my application would be to allow bulk re-configuration of IP addresses on units on a different subnet.

Regards

Dave
answered Oct 12, 2010 by david.lockyer New to the Community (15 points)
0 votes
I am also getting the same "No such file or directory" error when attempting to broadcast on a local subnet (with subnetmask 255.255.0.0). Have you found any resolution to this issue? Any help would be appreciated.

I am using Netos 7.4.2.
answered Dec 11, 2010 by fyicc New to the Community (18 points)
0 votes
I am hoping that by now yo got this issue corrected. There was an issue with CIDR considerations in the tcp/ip stack taht was affecting the ability (among other nasties) to send out local subnet broadcasts. There was a patch issued to address this issue.
answered May 3, 2011 by dakotas_dad Veteran of the Digi Community (694 points)
0 votes
I had contacted Digi support and they could not reproduce the problem. However, not too long after contacting support, a firmware was released that fixed UDP broadcasts. Coincidence?
answered May 3, 2011 by fyicc New to the Community (18 points)
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