we run wowza on port 1936 and one customer is asking to change back to 1935 because:
you must open up both 1935 and 80 for Wowza or you will get a lot of people that won't be able to connect to it as 1936 isn't common at all to have open on firewalls for more properly locked down systems.
If port 1936 is open on your server, and you specify port 1936 in all your URLs, it should work. However it is possible for a system admin to block traffic on their LAN for any port. With Flash RTMP clients you can do port and protocol rollover.