Re: Socket question

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"Alun Jones" <alun@xxxxxxxxxxxxx> wrote in message news:OUzDcY6WJHA.4384@xxxxxxxxxxxxxxxxxxxxxxx
"m" <m@xxx> wrote in message news:#CAFxcNWJHA.1576@xxxxxxxxxxxxxxxxxxxxxxx
False!

<snip>
because no 2 sockets share same
source IP/source port
</snip>

This is only true for outbound connections. A server app has many sockets with the same local IP and port.

This isn't even true for outbound connections.

The only guarantee of uniqueness necessary (or provided) is that the combination of { protocol, source address, source port, destination address, destination port } is unique.

What may have confused you is that an unconnected socket has destination address and port set to 0, but again, those sockets only need to be unique if they are used as TCP listeners or unicast UDP receivers.
That's right. However, you need to explicitly bind sockets to specific port for that (so that more than one outbound socket use same src port) and use SO_REUSEADDR option. Without such explicit steps, same src port won't be used by multiple sockets.

Boris

.

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