Greetings. I have a general (and probably simple) question about the
syntax of the filter rules. I noticed that in the default rule set, it
takes two rules to allow a single TCP port. For example, to allow TCP
port 1723, I need to have:

"Any Any Any Any TCP 1723 Any" and
"Any Any Any Any TCP Any 1723"

But for UDP (port 500), it only requires one rule "Any Any Any Any UDC
500 500".

Will it work if I use only one rule for TCP like "Any Any Any Any TCP
1723 1723"? (I know I could have tried it myself but I am afraid I will
disrupt the VPN service.)

Could someone please enlighten me on why we need to break TCP into two
rules, but only one rule for UDP?

Many thanks.

Patrick