Need to create irule that can redirect a port to another port

for the port part a quick search turns this up

According to RFC2965 3.3.1 (which might or might not be followed by browsers), unless the port is explicitly specified via the port parameter of the Set-Cookie header, cookies might or might not be sent to any port.

Google's Browser Security Handbook says: by default, cookie scope is limited to all URLs on the current host name - and not bound to port or protocol information. and some lines later There is no way to limit cookies to a single DNS name only [...] likewise, there is no way to limit them to a specific port. (Also, keep in mind, that IE does not factor port numbers into its same-origin policy at all.)

so that isn't the case most likely.

how does that work when you go normally to the site without a F5, you then also go on different ports right?

for the irule just search here, tinkering with ports is often requested and with some searching and putting parts together you probably will go something working. personally i still doubt it will be able to do what you want.