A recent study by RIPE (the European Internet Registry for IP addresses) has warned that by 2011 the current version of IP addresses (IPv4) will be depleted, thus it urged all professional bodies and organizations dealing with the Internet to actively adopt and support the new IPv6 address version.
IPv6 addresses are 128 bits long-much longer [...]

Multimedia applications (such as RealAudio, VoIP Telephony, Video Streaming etc) were always an issue when passing through a network firewall. These kind of applications behave in unique ways:

They use dynamic ports.
They transmit request using TCP and get responses in UDP or TCP.
They use the same port for source and destination.
For each multimedia request, the multimedia [...]

The Well Known Ports are assigned by the IANA and on most systems can only be used by system (or root) processes or by programs executed by privileged users.
Ports are used in the TCP [RFC793] to name the ends of logical connections which carry long term conversations. For the purpose of providing services to unknown [...]