Port translation for outbound with port range

Based in the snat command documentation, it just accepts one port: https://devcentral.f5.com/wiki/irules.snat.ashx

You need to keep track of the port used, saving the information to the persistence table. For a new connection you assign the port, and save the port in the persistence table. When the connection is finished (CLIENT_CLOSED event), you need to delete the table entry. You also need to write the logic to check for next available port in the range, maybe having a global variable with an index that you increment (and return to the beginning when reach the higest number), and check that does not exit yet in the persistence table.

Have a look in this link about the persistence table: https://devcentral.f5.com/articles/irules-101-12-the-session-command