A firewall can reside on your local machine, on a corporate firewall, or both. Have your IT department configure the firewall to accommodate these settings:
WEB & VIDEO INGEST
For broadcasting and viewing:
74.217.100.0/24
199.66.236.0/22
Ports: 80, 443, 1935 Traffic type: HTTP, HTTPS, RTMP
For using IRC CHAT while viewing streams the following ports also need to be opened:
Port 843 Flash Cross Domain Security XML File
Port: 6667 Traffic type: IRC
Here are links to adjusting firewall settings on local machines:
Mac OS: http://homepage.mac.com/car1son/static_port_fwd_firewall.html
Windows 7: http://windows.microsoft.com/en-US/windows-vista/Open-a-port-in-Windows-Firewall
Windows XP: http://support.microsoft.com/kb/308127