What local interface was connection or packet received on?

Question

When receiving a packet on an unconnected UDP socket bound to 0.0.0.0/INADDR_ANY, how can I determine what the local IP it was sent to?
Can I determine what interface it was received on?
Can this be also be done for connection-oriented sockets such as TCP?

Update0

Platform is Linux, so language is irrelevant but C is native.
UDP sockets are bound to INADDR_ANY host, so getsockname() returns 0.0.0.0.

Try this question: http://stackoverflow.com/questions/3940612/c-dgram-socket-get-the-receiver-address — Steve-o, Mar 07 '11 at 12:39

score 1 · Accepted Answer · answered Mar 07 '11 at 09:22

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Hmmm, have a look at this. So looks like there is probably a socket option, at least in the Linux/Unix world. What OSes does it need to work on?

answered Mar 07 '11 at 09:22

vulcan

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I've added the platform to the Q. – Matt Joiner Mar 07 '11 at 12:24

score 1 · Answer 2 · answered Mar 07 '11 at 10:36

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I've had to deal with the same issue on Windows platforms. My solution was to explicitly listen on all available interfaces as that way getsockname() works as expected.

answered Mar 07 '11 at 10:36

Len Holgate

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What local interface was connection or packet received on?

Update0

2 Answers2