send/receive udp from specific NIC

dsollen · 10-27-2009, 01:56 PM

well the title sort of says it all. I have a computer with multuple ethernet ports, I want to explicitly use one of those ethernet ports. I know I could configure routing at the OS level to ensure specific port numbers go to a NIC, but is there a way I can control which NIC I use from within a C++ program without modifying the OS?

FYI I'll be running in a linux enviroment.

Thanks.

valaris · 10-27-2009, 04:30 PM

You can specify what interface you are binding to when calling bind(). That being said which ever interface gets to this port first will own it until it releases it.

brewbuck · 10-27-2009, 04:55 PM

When you bind, instead of specifying INADDR_ANY, specify the actual IP address of the interface you want to bind to.

EDIT: The answer is the same if you want to specify the interface for OUTGOING packets as well. Normally, for outgoing packets, you do not bother binding, but that doesn't mean you can't. bind to the proper IP and it should work how you want.

10-27-2009, 01:56 PM	#1
dsollen Registered User Join Date: Oct 2009 Posts: 3	send/receive udp from specific NIC well the title sort of says it all. I have a computer with multuple ethernet ports, I want to explicitly use one of those ethernet ports. I know I could configure routing at the OS level to ensure specific port numbers go to a NIC, but is there a way I can control which NIC I use from within a C++ program without modifying the OS? FYI I'll be running in a linux enviroment. Thanks.
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10-27-2009, 04:30 PM	#2
valaris Registered User Join Date: Jun 2008 Location: RING 0 Posts: 462	You can specify what interface you are binding to when calling bind(). That being said which ever interface gets to this port first will own it until it releases it.
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10-27-2009, 04:55 PM	#3
brewbuck Senior software engineer Join Date: Mar 2007 Location: Portland, OR Posts: 5,381	When you bind, instead of specifying INADDR_ANY, specify the actual IP address of the interface you want to bind to. EDIT: The answer is the same if you want to specify the interface for OUTGOING packets as well. Normally, for outgoing packets, you do not bother binding, but that doesn't mean you can't. bind to the proper IP and it should work how you want. __________________ "Congratulations on your purchase. To begin using your quantum computer, set the power switch to both off and on simultaneously." -- raftpeople@slashdot
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