Cisco's Preferred Architecture states unauthenticated calls should be restricted from reaching protected resources such as the PSTN, including via the Calling Search Space on Unified CM.

Checked 2026-09-25

unauthenticated calls should be restricted from access to protected resources such as the PSTN
Vendor
Cisco
Product
Cisco Expressway with Cisco Unified CM
Subsystem
toll fraud
Deployment
on-premises
Region
not restricted
Release range
Collaboration 14
Checked
2026-09-25

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). Setting up business-to-business calling on Cisco Expressway: source note expressway-b2b-setup-pa-unauth-no-pstn. WarmTransfer. https://warmtransfer.net/knowledge/claims/expressway-b2b-setup-pa-unauth-no-pstn

BibTeX

@misc{warmtransfer-claim-expressway-b2b-setup-pa-unauth-no-pstn,
  title  = {Setting up business-to-business calling on Cisco Expressway: source note expressway-b2b-setup-pa-unauth-no-pstn},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/expressway-b2b-setup-pa-unauth-no-pstn},
  note   = {Source note expressway-b2b-setup-pa-unauth-no-pstn, checked 2026-09-25}
}

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