Re: IP address used by Sockets

[Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx>]

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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