Broadcast UDP packets don't go to all network interfaces in Vista

[ED]

Hi,

my application issues a Broadcast UDP packet, but it goes only to one of two
interface cards, connected to the office LAN. Only when I switch off that
LAN, Broadcast packet goes to the second interface card connected to an IP
device.
Firewall is switched off.

What could be the cause?

Ed

[Patrick Klos]

Post by ED
Hi,
my application issues a Broadcast UDP packet, but it goes only to one of two
interface cards, connected to the office LAN. Only when I switch off that
LAN, Broadcast packet goes to the second interface card connected to an IP
device.
Firewall is switched off.
What could be the cause?

Last time I was doing UDP broadcasts, I had to enumerate the interfaces and
send a local broadcast on each interface. If I recall correctly, the process
started with getting my own host's name (gethostname()) and feeding that name
into gethostbyname(), which would return a list of IP addresses assigned to
the local host. Then you could bind a DGRAM socket to each local interface
and send the broadcast from that socket. I don't have my code handy to be
100% sure, but that's the gist of it.

Patrick
========= For LAN/WAN Protocol Analysis, check out PacketView Pro! =========
Patrick Klos Email: ***@klos.com
Klos Technologies, Inc. Web: http://www.klos.com/
============================================================================

[ED]

Hi Patrick,

thanks for your reply!
So did I: enumerated interfaces with GetAdaptersInfo and sent subnet
broadcasts
instead of a global broadcast. It works for Vista OK.

Post by Patrick Klos
Last time I was doing UDP broadcasts, I had to enumerate the interfaces and
send a local broadcast on each interface. If I recall correctly, the process
started with getting my own host's name (gethostname()) and feeding that name
into gethostbyname(), which would return a list of IP addresses assigned to
the local host. Then you could bind a DGRAM socket to each local interface
and send the broadcast from that socket. I don't have my code handy to be
100% sure, but that's the gist of it.
Patrick
========= For LAN/WAN Protocol Analysis, check out PacketView Pro! =========
Klos Technologies, Inc. Web: http://www.klos.com/
============================================================================