For basic XMPP functionality, the client has to be able to connect to exactly one remote port (5222). This is not the same as an ‘open port’, as the latter usua

For basic XMPP functionality, the client has to be able to connect to exactly one remote port (5222). This is not the same as an ‘open port’, as the latter usually implies allowing incoming connections on this port. You can easily run a XMPP server on any port you like, so it would also be possible to only require outgoing connection to, say, port 443. Thanks to TLS, this is somewhat indistinguishable from native HTTPS traffic. Regarding your problem with BOSH: Simply build your own library and everything is fine if you don’t like the GPL. Not really the problem of the rest of the world. Furthermore, you cannot do ‘the same thing’ using HTTP 1.1 as you can with XMPP – the former is a somewhat trivial c2s transport protocol, the latter is a complex, extensible protocol allowing both c2s, s2s, c2c and c2s2s2c connections. You don’t really compare the vfat module in Linux to the Windows kernel either.