Symantec Security 5600 Series, Security 5400 Series,Clientless VPN 4400 Series, Administration Manual

Page: 203 / 861

203 Defining your security environment
Controlling full application inspection of traffic
Controlling Internet-based data communications
H.323 is an International Telecommunications Union (ITU) standard that supports the transmission of
real-time video, audio, and data. The security gateway provides support for the H.323 protocol through
the included H.323 application proxy. Programs using the H.323 standard communicate over the
Internet and interact with other H.323 compliant hosts.
The security gateway does not support the following H.323 elements:
■
Multicast addressing
■
LDAP with H.323
How the security gateway handles H.323 traffic
The security gateway supports H.323 connections both non-transparently and directly.
How non-transparent connections hide addresses
The security gateway hides the addresses of hosts behind it. Unless an address transform is configured
to reveal the addresses of hosts the security gateway protects, connecting clients see only the security
gateway’s outside interface address. To receive inbound H.323 connections when the internal network
address is hidden (non-transparent), additional configuration is required.
For non-transparent connections, you must do two things for the connection to find its final
destination:
■
Create an alias file
■
Establish an H.323 security gateway on the remote NetMeeting Client (NetMeeting only)
In Figure 6-1 , the inside client’s address is hidden. The outside user sees the outside interface of the
security gateway (172.16.0.1).
Figure 6-1
Address hiding with H.323
The connection that the security gateway manages is between the two NetMeeting clients, but instead
of revealing the 192.168.0.5 address of the internal client, the security gateway replaces the address
with its own outside interface address, 172.16.0.1.
NetMeeting client
NetMeeting client
Security gateway
192.168.0.6
192.168.0.5
192.168.0.1 172.16.0.1
10.1.1.15
Internet
Inside Outside