Re: IP address used by Sockets

The bind() API can be used to force a TCP socket to use a particular IP address, as Michael already explained. Set the port to 0 to let the OS choose the port.

However, this doesn't make sense to do. IF your TCP/IP routes are configured properly, it will automatically pick the correct IP address. If the routes aren't configured properly, binding to a particular address won't help you, because the packets still need to be routed correctly for the connection to work.

So this doesn't make a lot of sense to me.

Binding to a particular IP address is a tool usually used on a listening server program so that you can (for example) listen on your internal subnet without allowing access from the public internet. Stuff like that. It doesn't make sense to use in a client program -- at least not in my experience.

I wonder if you don't have a misconfigured route somewhere?



Joe Wells wrote:

Our 400 has two IP addresses.

Using Scott Klement's socket utilities service program, I have created
working client and server programs.

Here is my dilemma - our network folks established a secure connection
(tunnel?) between us and another system. The problem is that the one of my
socket programs is now using the "other" ip address on our 400. Consequently, this program cannot connect!

So, my question is - Is there a way to specify the outbound IP address the
socket uses?

Thanks,

Joe

Joe Wells
University of Alabama Health Services Foundation
500 22nd Street South, Suite 308
Birmingham, AL 35233
205-731-5610

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