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Cisco PIX Firewall and VPN Configuration Guide
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Chapter 1 Getting Started
Supporting Specific Protocols and Applications
When coupled with an H.323 Proxy, an SCCP client can interoperate with H.323 compliant terminals.
Application inspection in the PIX
Firewall works with SCCP Version 3.1.1. The functionality of
PIX
Firewall application inspection ensures that all SCCP signalling and media packets can traverse the
Firewall by providing NAT of the SCCP signaling packets.
Note PIX Firewall Version 6.3 introduces PAT support for SCCP.
SIP
Session Initiation Protocol (SIP) enables call handling sessions—particularly two-party audio
conferences, or “calls.” The PIX
Firewall supports SIP VoIP gateways and VoIP proxy servers. It also
supports definition using SDP for dynamically allocated UDP ports. In addition, SIP supports the Instant
Messaging (IM) Chat feature on Windows XP using Windows Messenger RTC Client version 4.7.0105
only.
Multimedia Applications
Users increasingly make use of a wide range of multimedia applications, many of which require special
handling in a firewall environment. The PIX
Firewall handles these without requiring client
reconfiguration and without becoming a performance bottleneck. The specific multimedia applications
supported by the PIX
Firewall include the following:
• RealAudio
• Streamworks
• CU-SeeMe
• Intel Internet Phone
• IRC
• Vxtreme
• VDO Live
Note Traffic using specific protocols can be prevented using access lists.
The PIX Firewall allows the secure forwarding of Real Time Streaming Protocol (RTSP) packets. RTSP
is used by RealAudio, RealNetworks, Apple QuickTime 4, RealPlayer, and Cisco IP/TV connections.
This feature lets the firewall handle multimedia applications including Cisco IP/TV connections.
Note PIX Firewall does not yet have the ability to recognize HTTP cloaking where an RTSP message is hidden
within an HTTP message. Also, RTSP is not supported with NAT.
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