Network Delivery Mechanisms - A Practical Guide to Video and Audio Compression - page 341

Table 19-2 TCP Port Numbers for Streaming

Port Usage

You can tunnel RTSP and RTP traffic through port 80 as if it were an
HTTP connection.

80

This port number is used for RTSP.

554

This port number can be used for RTSP instead of 554 . This avoids using
a number in the lower 1000 port numbers that are considered special from
a secure-access point of view. Firewalls may be configured to disallow
connections to ports in the lower 1000 range.

7070

6970 - 9999

These ports can be allowed for UDP connection but on a requested basis.
You may want to ensure they are only requested by authentic sessions
that may have been initiated on another port first.

This port number is sometimes used for Web administration.

1220

A high-numbered port, this is occasionally allocated for HTTP use as an
alternative to port 80 .

8080

This port number is sometimes opened for Mac OS X Server Admin.

311

Other useful tools that help you to look up network addresses are listed in
Table 19-3.

19.10 Virtual Private Networks

In times past, large organizations would lease landlines from telecoms suppliers to con-
nect their various offices together. This meant that even though they had a somewhat
physical connection to one another, the networks were secure and very hard to penetrate
because they were not connected to the rest of the world at any point outside of very
secure switching centers.
Then the corporate organizations began to put Internet gateways on their networks,
and so different companies were able to send e-mail and exchange files.
With the advent of the World Wide Web in the early 1990s, the Internet took off and
companies then deployed firewalls and proxy servers in order to facilitate Web browsing
from within the corporate network. This also provided the opportunity to connect
their sites to one another via the Internet. As this required a much more secure connection,
various protocols and services were evolved into virtual private networks (VPNs). These
are secure connections between two sites belonging to the same company and are delivered
on the basis of a guaranteed minimum level of bit rate that is reserved for that VPN.
A typical use for a VPN is to connect a Web content-creation HQ to the server farm,
which is normally located in a bunker for resilience.