My experience is the exact opposite: all networks I've used in the US (Sprint, Verizon, AT&T, and T-Mobile; in essence, all of the major ones) and the few I've used in the UK (while roaming) have all had sufficiently few outgoing ports blocked that I've never run into one (and I use my iPhone as if it were a computer ;P). That said, WebSockets is just an upgrade extension to HTTP, so it is going to go over 80/443 anyway.