Sip Inspection; Sip Inspection Overview - Cisco PIX 500 Series Configuration Manual

Chapter 25 Configuring Application Layer Protocol Inspection
The following example shows a how to define an RTSP inspection policy map.
hostname(config)# regex badurl1 www.url1.com/rtsp.avi
hostname(config)# regex badurl2 www.url2.com/rtsp.rm
hostname(config)# regex badurl3 www.url3.com/rtsp.asp
hostname(config)# class-map type regex match-any badurl-list
hostname(config-cmap)# match regex badurl1
hostname(config-cmap)# match regex badurl2
hostname(config-cmap)# match regex badurl3
hostname(config)# policy-map type inspect rtsp rtsp-filter-map
hostname(config-pmap)# match url-filter regex class badurl-list
hostname(config-pmap-p)# drop-connection
hostname(config)# class-map rtsp-traffic-class
hostname(config-cmap)# match default-inspection-traffic
hostname(config)# policy-map rtsp-traffic-policy
hostname(config-pmap)# class rtsp-traffic-class
hostname(config-pmap-c)# inspect rtsp rtsp-filter-map
hostname(config)# service-policy rtsp-traffic-policy global

SIP Inspection

This section describes SIP application inspection. This section includes the following topics:
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SIP Inspection Overview

SIP, as defined by the IETF, enables call handling sessions, particularly two-party audio conferences, or
"calls." SIP works with SDP for call signalling. SDP specifies the ports for the media stream. Using SIP,
the security appliance can support any SIP VoIP gateways and VoIP proxy servers. SIP and SDP are
defined in the following RFCs:
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To support SIP calls through the security appliance, signaling messages for the media connection
addresses, media ports, and embryonic connections for the media must be inspected, because while the
signaling is sent over a well-known destination port (UDP/TCP 5060), the media streams are
dynamically allocated. Also, SIP embeds IP addresses in the user-data portion of the IP packet. SIP
inspection applies NAT for these embedded IP addresses.
The following limitations and restrictions apply when using PAT with SIP:
OL-12172-03
hostname(config-pmap-p)# url-length-limit length
Where the length argument specifies the URL length in bytes (0 to 6000).
SIP Inspection Overview, page 25-65
SIP Instant Messaging, page 25-66
Configuring SIP Timeout Values, page 25-70
Verifying and Monitoring SIP Inspection, page 25-71
SIP: Session Initiation Protocol, RFC 3261
SDP: Session Description Protocol, RFC 2327
Cisco Security Appliance Command Line Configuration Guide
SIP Inspection
25-65