These three terms are common for network & firewall guy. However others who are not working in this are normally doesn’t really know what is the meaning of this terms.
The problem start when people requesting to open certain network port from certain source to certain destination. However, they don’t really understand what of the meaning of this terms even though we've prepared proper form for them to fill up these informations. Sometimes, they put destination at source column and always forget to put either TCP/UDP. Normally they only put the number of the ports. Here is the example of the form.
|Source IP||Destination IP||Service (TCP/UDP)||Port Number|
Therefore, I would appreciate if anyone can share how to explain these terms in easy way especially to those who didn’t have knowledge in networking.