Ok I roughly know what ports are....and how to open them and forward them etc. However Im a bit confused about how they are assigned by applications. For example SMTP uses port 25...so does this leave my ISP mail server on port 25 and then come into my exchange server on port 25?.
The reason Im confused boils down to the difference between local and remote ports?.
Can someone give me a good analogy that will make sence of this to me?.