Source note · Calls that drop after about 30 seconds
Cisco recommends turning off SIP ALG, or similar SIP-aware functions, on routers and firewalls carrying Webex Calling traffic, because some ALG implementations cause firewall traversal problems.
Checked 2026-09-25
If a router or firewall is SIP Aware, implying that the SIP Application Layer Gateway (ALG) or similar is enabled, we recommend you turn off this functionality for accurate operation of the service.
- Vendor
- Cisco
- Product
- Webex Calling
- Subsystem
- network / firewall
- Deployment
- multi-tenant
- Region
- not restricted
- Release range
- current as of 2026-09-25
- Checked
- 2026-09-25
Sources
- Port Reference Information for Webex Calling — Cisco Systems, Inc. (help.webex.com) · tier 2 current vendor documentation · Section 'SIP Application Layer Gateway'
Cite this note
APA
WarmTransfer. (2026, September 25). Calls that drop after about 30 seconds: source note sip-calls-drop-30-seconds-webex-disable-alg. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-calls-drop-30-seconds-webex-disable-alg
BibTeX
@misc{warmtransfer-claim-sip-calls-drop-30-seconds-webex-disable-alg,
title = {Calls that drop after about 30 seconds: source note sip-calls-drop-30-seconds-webex-disable-alg},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-calls-drop-30-seconds-webex-disable-alg},
note = {Source note sip-calls-drop-30-seconds-webex-disable-alg, checked 2026-09-25}
}