RE: Netmeeting traffic

From: Cheung, Rick (Rick.Cheung@NextelPartners.com)
Date: Thu Jan 24 2002 - 11:44:16 EST


        Felix, NBar may be able to recognize Netmeeting traffic. The hard
part with protecting Netmeeting traffic with QOS is that it has the concept
of primary and secondary ports. The primary ports are defined by Microsoft
in the text below.

        The secondary ports are anywhere from 1024-65535.

http://www.microsoft.com/windows/netmeeting/corp/reskit/appendixb/default.as
p

Unable to connect to a directory server through a firewall
Many organizations use a security system known as a firewall to protect
against external threats to the network. A firewall prevents computers in
the organization's network from communicating directly with computers
external to the network, and vice versa. All communication is routed through
a proxy server that decides whether it is safe to let data pass through to
the organization's network.

Sometimes the proxy server will limit certain ports because of security
concerns. The proxy server must be configured so that the ports used by
NetMeeting are not blocked.

To allow NetMeeting to communicate fully, the following ports need to be
available on the proxy server:

389 LDAP (TCP)
522 User Location Server (TCP)
1503 T.120 protocol (TCP)
1720 H.323 call setup (TCP)
1731 Audio call control (TCP)
Dynamic H.323 call control (TCP)
Dynamic H.323 streaming [Real-Time Transport Protocol (RTP) over User
Datagram Protocol (UDP)]
To establish outbound NetMeeting connections through a proxy server, the
proxy server must be configured to do the following:

Pass through primary TCP connections on ports 389, 522, 1503, 1720, and
1731.
Pass through secondary UDP connections on dynamically assigned ports
(1024-65535).
Some proxy servers can pass through TCP connections on specific ports, but
cannot pass through secondary UDP connections on dynamically assigned ports.

Some firewalls can pass through TCP connections on specific ports and
secondary UDP connections on dynamically assigned ports, but cannot
virtualize an arbitrary number of IP addresses, or cannot do so dynamically.

With these proxy servers, you can establish NetMeeting connections from
computers inside the firewall to computers outside the firewall and use the
audio and video features of NetMeeting, but you cannot establish connections
from computers outside the firewall to computers inside the firewall.

If your computer and the remote computer are trying to connect with are
behind proxy servers, consider using a Multipoint Control Unit (MCU).

Rick Cheung
mailto:rick.cheung@nextelpartners.com

-----Original Message-----
From: Felix Lee [mailto:felixlee_hk@hotmail.com]
Sent: Wednesday, January 23, 2002 8:11 PM
To: cisco-nsp@puck.nether.net
Subject: Netmeeting traffic

Dear all,

In order to have better control of Microsoft Netmeeting 3.0 traffic, would
someone help to provide the follow TCP or UDP port number to me?

- Application sharing (like Powerpoint, Excel ...etc)
- White board sharing
- Online chatting
- Video communication
- Audio communication

Thanks!

FL

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