CLI Book 2: Cisco Secure Firewall ASA Firewall CLI Configuration Guide 9.23 - Inspection for Voice and Video Protocols

Publisher

Cisco Systems

URL

https://www.cisco.com/c/en/us/td/docs/security/asa/asa923/configuration/firewall/asa-923-firewall-config/inspect-voicevideo.html

Published

2026-07-17

Updated

unknown

Accessed

2026-09-25

HTTP status

200

License

Cisco copyright; all rights reserved; no-redistribution; short excerpts and locators only

Source notes citing this source

• The ASA default SIP inspection does not inspect encrypted SIP. A TLS proxy must be configured for that. in context
• With PAT on the ASA, a SIP header field that contains an internal IP address without a port might not be translated, leaking the internal address outside. Cisco suggests NAT instead of PAT to avoid this. in context
• If a SIP device sends SDP whose o= (owner/creator) IP differs from the c= (connection) IP, the ASA with PAT may not translate the o= address properly because the o= field has no port. in context
• On Cisco Secure Firewall ASA, SIP inspection is enabled by default through the default inspection policy. in context
• If a capture on the public side of a PAT device shows a private address still present in a SIP header or in the SDP o= field while other fields were translated, that pattern matches documented partial-translation limits of SIP inspection. It is not proof that no ALG is present. inferred in context

Cite this source record

APA

WarmTransfer. (2026, July 17). CLI Book 2: Cisco Secure Firewall ASA Firewall CLI Configuration Guide 9.23 - Inspection for Voice and Video Protocols. WarmTransfer. https://warmtransfer.net/knowledge/sources/cisco-asa-923-inspect-voice-video

BibTeX

@misc{warmtransfer-cisco-asa-923-inspect-voice-video,
  title  = {CLI Book 2: Cisco Secure Firewall ASA Firewall CLI Configuration Guide 9.23 - Inspection for Voice and Video Protocols},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/sources/cisco-asa-923-inspect-voice-video},
  note   = {Cisco Systems, accessed 2026-09-25}
}