
Firewalls are administered by corporations to prevent unauthorized access
to corporate networks. Most firewalls are based on packet filtering.
Packet filtering takes place when the computer examines the source and
destination IP addresses of a packet and forwards only those packets
for which access has been granted.
Additional information on firewalls is also available 
in ASF form and
in
Q & A form.
NetShow content streaming from Microsoft NetShow
will stream through
a number of firewalls, and we are working with many additional
vendors for support in their products. This page on
on http://www.microsoft.com/netshow/firewall.htm will be updated
periodically as more firewall vendors add support for NetShow.
If you are a firewall vendor and would like to be listed
as supporting NetShow, please send e-mail to
nssubmit@microsoft.com.
advanced information on passing NetShow traffic through firewalls is available.