# Webex for Government calling restrictions Canonical: https://warmtransfer.net/knowledge/webex-calling-webex-for-government Last verified: 2026-09-24 Webex for Government calling restricts available trunking architectures, gateway hardware, and specific calling capabilities relative to standard multi-tenant deployments[^49][^36]. The environment operates under a FedRAMP Moderate impact level authorization with all data centres located in the continental United States[^15]. ## Local Gateway and PSTN architecture PSTN connectivity in Webex for Government relies exclusively on Local Gateway deployments using Cisco Unified Border Element (CUBE)[^49][^10][^11]. At its initial 2023 release, Webex Calling in Webex for Government offered only Local Gateway options for PSTN connectivity[^19]. WarmTransfer's reading of the sources is that no current Cisco source reviewed documents a PSTN connectivity option for Webex for Government Calling other than a certificate-based CUBE Local Gateway[^39]. In addition, Cisco Calling Plans, including plans offering business texting (SMS), are not supported[^33]. Trunking to the Local Gateway requires certificate-based authentication; registration-based trunking is completely unsupported[^49][^51][^35][^8]. Certificate-based Local Gateway trunks use certificate-based authentication with Local Gateway FQDN verification rather than digest authentication, and they support more than 250 concurrent calls per trunk compared to the 250 concurrent call limit on registration-based trunks[^6][^7]. Third-party session border controllers are not supported for Webex for Government[^49][^51][^29]. WarmTransfer's reading of the sources is that a third-party SBC such as a Ribbon or AudioCodes unit cannot serve as the Webex-facing Local Gateway in a Webex for Government deployment[^1]. Local Gateways must adhere to strict software and security baselines: - Local Gateways must run Cisco IOS XE Dublin 17.12.1a or later[^50][^18]. - FIPS-compliant GCM ciphers are mandatory on the Local Gateway, and call setup fails without them[^17]. - STUN/ICE-Lite for media path optimization is not supported on the Local Gateway[^22]. - T.38 fax is not supported on the Local Gateway[^23]. The Local Gateway configuration documentation points administrators to an approved root certificate authority list[^41]. Cisco publishes a Cisco Trusted FedRAMP Root Bundle at https://www.cisco.com/security/pki/trs/fedramp.p7b[^16]. This root CA list includes commercial roots such as DigiCert and Entrust alongside US DoD CCEB Interoperability Root CA 2 and WidePoint NFI Root 2[^40]. WarmTransfer's reading of the sources is that a certificate-based Local Gateway for Webex for Government should present a certificate chaining to an entry on this root CA list[^20]. ## Network and administrative environment All Webex for Government traffic requires TLS 1.2 or TLS 1.3, and mTLS is mandatory for on-premises SIP registered devices[^42]. Network allowlists must permit *.webexgov.us, alongside standard domains including *.webex.com, *.wbx2.com, and *.ciscospark.com[^45]. Administrators manage their environment through Control Hub at https://admin-usgov.webex.com[^9]. In June 2023 Cisco announced that Webex Calling would be included in Webex for Government with FedRAMP moderate authorization, targeted for Fall 2023[^14]. Cisco later announced its availability as FedRAMP Moderate authorized, delivered from compliant data centres within the United States[^3]. Note that the Get started with Webex for Government page describes cloud calling as Unified CM Cloud for Government with Cisco IP Phones rather than multi-tenant Webex Calling[^43]. Licensing under the Webex for Government Flex 3.0 datasheet includes Professional, Standard, and Workspace licenses, with the Standard tier restricted to a single device[^13]. ## Calling feature support Webex for Government Calling disables several standard calling features and add-ons: - Site survivability is unsupported[^36], although Cisco's 2023 launch post stated that survivability options were planned for future releases[^4]. - Third-party call recording and Call Recording Partner integrations are not supported[^28][^25]. - WebRTC is not supported[^38]. - Third-party SIP devices are not supported[^30]. - PIN Lock is not supported on Desk Series devices[^34]. - Webex App Hub marketplace integrations are unsupported[^32]. - AI Receptionist and AI Assistant are unsupported[^31]. - Webex Go Mobile Operator, Attendant Console, and Digital Fax Messaging are not supported[^25]. Supported administrator-configured features include Auto Attendant, Call Queue, Call Pickup, Call Park, Hunt Group, Paging Group, and Receptionist Client[^2]. Supported user-configured features include call forwarding variants, do not disturb, office anywhere, remote office, sequential ring, and simultaneous ring[^44]. ## See also - [Webex Calling architecture and deployment models](https://warmtransfer.net/knowledge/webex-calling-architecture) - [Webex Calling Dedicated Instance applicability](https://warmtransfer.net/knowledge/webex-calling-dedicated-instance) - [Webex Calling PSTN options and selection](https://warmtransfer.net/knowledge/webex-calling-pstn-options) - [Webex Calling Site Survivability Gateway](https://warmtransfer.net/knowledge/webex-calling-survivability-gateway) - [Webex Calling supported devices and MPP firmware](https://warmtransfer.net/knowledge/webex-calling-device-support) - [Webex Calling license types and entitlements](https://warmtransfer.net/knowledge/webex-calling-licensing) - [Webex Calling calling features and feature parity vs UCM](https://warmtransfer.net/knowledge/webex-calling-features) - [Webex Calling AI Receptionist](https://warmtransfer.net/knowledge/webex-calling-ai-receptionist) - [Webex Calling Call Queue as a product](https://warmtransfer.net/knowledge/webex-calling-call-queue) ## Applicability Applies to: Cisco Webex Calling, Cisco IOS XE (CUBE), and Cisco Webex for Government. Deployments: multi-tenant, dedicated instance, and premises-based-pstn. Sources checked 2026-09-24. Webex for Government requires Cisco IOS XE Dublin 17.12.1a or later on the Local Gateway[^50][^18]. ## What remains uncertain Cloud Connected PSTN availability for Webex for Government is not covered by the sources below. E911 and RedSky provisioning in a Webex for Government org is not covered by the sources below. Native call recording support in Webex for Government is not covered by the sources below. FedRAMP High or DoD IL status for Webex Calling is not covered by the sources below. The relationship of UCM Cloud for Government to Webex Calling for Government is not covered by the sources below. Supported phone models for Webex Calling in Webex for Government are not covered by the sources below. Webex Go and Business Texting entries on the gov What's new page are not covered by the sources below. Exact IOS XE ciphersuite commands for gov LGW are not covered by the sources below. ## Sources [^1]: In a Webex for Government deployment a third-party SBC such as a Ribbon or AudioCodes unit cannot serve as the Webex-facing Local Gateway (inferred). Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), section Webex for Government. Checked 2026-09-24. [^2]: Webex for Government Calling supports administrator-configured Auto Attendant, Call Queue, Call Pickup, Call Park, Hunt Group, Paging Group and Receptionist Client. Source: [Webex for Government Calling](https://help.webex.com/en-us/article/n592cco/Webex-for-Government-Calling), supported features table (administrator-configured). Checked 2026-09-24. [^3]: Cisco announced Webex Calling in Webex for Government as FedRAMP Moderate authorized and delivered from FedRAMP Moderate compliant data centres in the United States. Source: [Webex Calling with FedRAMP authorization is available for government collaboration](https://blog.webex.com/collaboration/fedramp-authorization-for-government-collaboration/), opening paragraphs. Checked 2026-09-24. [^4]: Cisco's 2023 launch post described survivability options as planned for future Webex for Government Calling releases. Source: [Webex Calling with FedRAMP authorization is available for government collaboration](https://blog.webex.com/collaboration/fedramp-authorization-for-government-collaboration/), paragraph on future releases. Checked 2026-09-24. [^5]: The Webex for Government network requirements list IP subnets for Webex Calling services including 23.89.18.0/23, 163.129.16.0/21 and 144.196.224.0/21. Source: [Network requirements for Webex for Government (FedRAMP)](https://help.webex.com/en-us/article/n71sm9e/Network-requirements-for-Webex-for-Government-(FedRAMP)), IP subnets for Webex Calling services. Checked 2026-09-24. [^6]: Certificate-based Local Gateway trunks support more than 250 concurrent calls per trunk, whereas registration-based trunks support up to 250. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), certificate-based vs registration-based trunk comparison table. Checked 2026-09-24. [^7]: Certificate-based Local Gateway trunks use certificate-based authentication with Local Gateway FQDN verification instead of digest authentication. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), certificate-based vs registration-based trunk comparison table. Checked 2026-09-24. [^8]: Local Gateways in Webex for Government are to be configured with certificate-based trunking. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), section Webex for Government. Checked 2026-09-24. [^9]: Webex for Government administrators access Control Hub at https://admin-usgov.webex.com. Source: [Set up your Webex organization (Webex for Government)](https://help.webex.com/article/wmhul0/), opening note on Control Hub access. Checked 2026-09-24. [^10]: CUBE is the only session border controller that currently supports Webex for Government. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), section Webex for Government. Checked 2026-09-24. [^11]: The Webex for Government Flex 3.0 datasheet states that CUBE is supported in Webex Calling in Webex for Government as a Local Gateway for PSTN connectivity. Source: [Cisco Collaboration Flex Plan - Webex for Government - Collaboration Flex Plan 3.0 Data Sheet](https://www.cisco.com/c/en/us/products/collateral/unified-communications/cisco-collaboration-flex-plan/collaboration-flex-plan3-fedramp-ds.html), Webex Calling section (PSTN connectivity). Checked 2026-09-24. [^12]: The Webex for Government Flex 3.0 datasheet describes an Enhanced Emergency (E911) service for Webex Calling with dynamic location support and routing to PSAPs. Source: [Cisco Collaboration Flex Plan - Webex for Government - Collaboration Flex Plan 3.0 Data Sheet](https://www.cisco.com/c/en/us/products/collateral/unified-communications/cisco-collaboration-flex-plan/collaboration-flex-plan3-fedramp-ds.html), emergency calling paragraph. Checked 2026-09-24. [^13]: The Webex for Government Flex 3.0 datasheet offers Webex Calling as Professional, Standard and Workspace licences, with Standard limited to a single device. Source: [Cisco Collaboration Flex Plan - Webex for Government - Collaboration Flex Plan 3.0 Data Sheet](https://www.cisco.com/c/en/us/products/collateral/unified-communications/cisco-collaboration-flex-plan/collaboration-flex-plan3-fedramp-ds.html), Named User and Enterprise Agreement licensing sections. Checked 2026-09-24. [^14]: In June 2023 Cisco announced that Webex Calling would be included in Webex for Government with FedRAMP moderate authorization, targeted for Fall 2023. Source: [Webex to broaden U.S. government portfolio with Webex Contact Center Enterprise and Webex Calling](https://blog.webex.com/collaboration/hybrid-work/webex-government-portfolio/), paragraph announcing Webex Calling availability. Checked 2026-09-24. [^15]: Webex for Government holds FedRAMP authorization at the Moderate impact level with all data centres in the continental U.S. Source: [Get started with Webex for Government](https://help.webex.com/en-us/article/ybobxq/Get-started-with-Webex-for-Government), introductory overview. Checked 2026-09-24. [^16]: Cisco publishes a Cisco Trusted FedRAMP Root Bundle for Webex for Government at https://www.cisco.com/security/pki/trs/fedramp.p7b. Source: [Root certificate authorities for Webex for Government](https://help.webex.com/default/article/nqb3d03), body text naming the Cisco Trusted FedRAMP Root Bundle link. Checked 2026-09-24. [^17]: FIPS-compliant GCM ciphers are mandatory on a Webex for Government Local Gateway and call setup fails without them. Source: [Configure Local Gateway on Cisco IOS XE for Webex Calling](https://help.webex.com/en-us/article/jr1i3r/Configure-Local-Gateway-on-Cisco-IOS-XE-for-Webex-Calling), Configure your Local Gateway for Webex for Government. Checked 2026-09-24. [^18]: All Webex for Government Local Gateways must run Cisco IOS XE Dublin 17.12.1a or later. Source: [Configure Local Gateway on Cisco IOS XE for Webex Calling](https://help.webex.com/en-us/article/jr1i3r/Configure-Local-Gateway-on-Cisco-IOS-XE-for-Webex-Calling), Local Gateway for Webex for Government > Key considerations. Checked 2026-09-24. [^19]: At its initial 2023 release, Webex Calling in Webex for Government offered only Local Gateway options for PSTN connectivity. Source: [Webex Calling with FedRAMP authorization is available for government collaboration](https://blog.webex.com/collaboration/fedramp-authorization-for-government-collaboration/), paragraph on PSTN connectivity. Checked 2026-09-24. [^20]: A certificate-based Local Gateway for Webex for Government should present a certificate that chains to a root CA on the Webex for Government root CA list (inferred). Source: [Configure Local Gateway on Cisco IOS XE for Webex Calling](https://help.webex.com/en-us/article/jr1i3r/Configure-Local-Gateway-on-Cisco-IOS-XE-for-Webex-Calling), Local Gateway for Webex for Government > Key considerations (root CA link). Checked 2026-09-24. [^21]: Webex for Government Local Gateway SRTP media uses UDP source ports 8000-48198 toward destination ports 8500-8700 and 19560-65535. Source: [Network requirements for Webex for Government (FedRAMP)](https://help.webex.com/en-us/article/n71sm9e/Network-requirements-for-Webex-for-Government-(FedRAMP)), Webex Calling ports table > Call media (SRTP) > Local Gateway row. Checked 2026-09-24. [^22]: Local Gateway for Webex for Government does not support STUN/ICE-Lite for media path optimization. Source: [Configure Local Gateway on Cisco IOS XE for Webex Calling](https://help.webex.com/en-us/article/jr1i3r/Configure-Local-Gateway-on-Cisco-IOS-XE-for-Webex-Calling), Local Gateway for Webex for Government section. Checked 2026-09-24. [^23]: Local Gateway for Webex for Government does not support T.38 fax. Source: [Configure Local Gateway on Cisco IOS XE for Webex Calling](https://help.webex.com/en-us/article/jr1i3r/Configure-Local-Gateway-on-Cisco-IOS-XE-for-Webex-Calling), Local Gateway for Webex for Government section. Checked 2026-09-24. [^24]: Webex for Government Local Gateway SIP TLS signalling goes from TCP source ports 8000-65535 to destination ports 5062 and 8934. Source: [Network requirements for Webex for Government (FedRAMP)](https://help.webex.com/en-us/article/n71sm9e/Network-requirements-for-Webex-for-Government-(FedRAMP)), Webex Calling ports table > Call signaling (SIP TLS) > Local Gateway row. Checked 2026-09-24. [^25]: Webex for Government does not support Call Recording Partner, Webex Go Mobile Operator, Attendant Console or Digital Fax Messaging. Source: [Features available by license type for Webex Calling](https://help.webex.com/en-us/article/n1qbbp7/Features-available-by-license-type-for-Webex-Calling), Webex for Government note after the features comparison table. Checked 2026-09-24. [^26]: The Webex Calling features-by-license article states that Webex for Government does not support Call Recording (disputed). Source: [Features available by license type for Webex Calling](https://help.webex.com/en-us/article/n1qbbp7/Features-available-by-license-type-for-Webex-Calling), Webex for Government note after the features comparison table. Checked 2026-09-24. [^27]: The Webex Calling features-by-license article states that Webex for Government does not support Business Texting (disputed). Source: [Features available by license type for Webex Calling](https://help.webex.com/en-us/article/n1qbbp7/Features-available-by-license-type-for-Webex-Calling), Webex for Government note after the features comparison table. Checked 2026-09-24. [^28]: Webex for Government Calling does not support third-party call recording. Source: [Webex for Government Calling](https://help.webex.com/en-us/article/n592cco/Webex-for-Government-Calling), unsupported features list. Checked 2026-09-24. [^29]: Webex for Government does not currently support any third-party session border controllers. Source: [Configure Local Gateway on Cisco IOS XE for Webex Calling](https://help.webex.com/en-us/article/jr1i3r/Configure-Local-Gateway-on-Cisco-IOS-XE-for-Webex-Calling), Local Gateway for Webex for Government > Key considerations. Checked 2026-09-24. [^30]: Webex for Government Calling does not support third-party SIP devices. Source: [Webex for Government Calling](https://help.webex.com/en-us/article/n592cco/Webex-for-Government-Calling), unsupported features list. Checked 2026-09-24. [^31]: Webex for Government Calling does not support AI Receptionist or AI Assistant. Source: [Webex for Government Calling](https://help.webex.com/en-us/article/n592cco/Webex-for-Government-Calling), unsupported features list. Checked 2026-09-24. [^32]: Webex for Government Calling does not support Webex App Hub, the third-party app marketplace. Source: [Webex for Government Calling](https://help.webex.com/en-us/article/n592cco/Webex-for-Government-Calling), unsupported features list. Checked 2026-09-24. [^33]: Webex for Government Calling does not support Cisco Calling Plans, including plans with business texting (SMS). Source: [Webex for Government Calling](https://help.webex.com/en-us/article/n592cco/Webex-for-Government-Calling), unsupported features list. Checked 2026-09-24. [^34]: Webex for Government does not support PIN Lock for Desk Series devices. Source: [Webex for Government known issues and limitations](https://help.webex.com/en-us/article/8k8has/Webex-for-Government-known-issues-and-limitations), device limitations section. Checked 2026-09-24. [^35]: Webex for Government does not support registration-based Local Gateway. Source: [Configure Local Gateway on Cisco IOS XE for Webex Calling](https://help.webex.com/en-us/article/jr1i3r/Configure-Local-Gateway-on-Cisco-IOS-XE-for-Webex-Calling), Overview > Local Gateway for Webex for Government; Key considerations. Checked 2026-09-24. [^36]: Webex for Government Calling does not support site survivability. Source: [Webex for Government Calling](https://help.webex.com/en-us/article/n592cco/Webex-for-Government-Calling), unsupported features list. Checked 2026-09-24. [^37]: Webex for Government Calling does not support Webex Go (disputed). Source: [Webex for Government Calling](https://help.webex.com/en-us/article/n592cco/Webex-for-Government-Calling), unsupported features list. Checked 2026-09-24. [^38]: Webex for Government Calling does not support WebRTC. Source: [Webex for Government Calling](https://help.webex.com/en-us/article/n592cco/Webex-for-Government-Calling), unsupported features list. Checked 2026-09-24. [^39]: No current Cisco source reviewed documents a PSTN connectivity option for Webex for Government Calling other than a certificate-based CUBE Local Gateway (inferred). Source: [Webex for Government Calling](https://help.webex.com/en-us/article/n592cco/Webex-for-Government-Calling), unsupported features list (Cisco Calling Plans; registration-based Local Gateway) read with t9xctu Webex for Government section. Checked 2026-09-24. [^40]: The Webex for Government root CA list includes US DoD CCEB Interoperability Root CA 2 and WidePoint NFI Root 2 alongside commercial roots such as DigiCert and Entrust. Source: [Root certificate authorities for Webex for Government](https://help.webex.com/default/article/nqb3d03), root CA list entries 1 4 5 6. Checked 2026-09-24. [^41]: The Local Gateway configuration article directs Webex for Government administrators to a separate list of root certificate authorities that Webex for Government supports. Source: [Configure Local Gateway on Cisco IOS XE for Webex Calling](https://help.webex.com/en-us/article/jr1i3r/Configure-Local-Gateway-on-Cisco-IOS-XE-for-Webex-Calling), Local Gateway for Webex for Government > Key considerations (root CA link to nqb3d03). Checked 2026-09-24. [^42]: All Webex for Government traffic requires TLS 1.2 or TLS 1.3, and mTLS is required for on-premises SIP registered devices. Source: [Network requirements for Webex for Government (FedRAMP)](https://help.webex.com/en-us/article/n71sm9e/Network-requirements-for-Webex-for-Government-(FedRAMP)), encryption requirement statement. Checked 2026-09-24. [^43]: The Get started with Webex for Government page describes its cloud calling as Unified CM Cloud for Government with Cisco IP Phones rather than multi-tenant Webex Calling. Source: [Get started with Webex for Government](https://help.webex.com/en-us/article/ybobxq/Get-started-with-Webex-for-Government), feature overview bullet on cloud calling. Checked 2026-09-24. [^44]: Webex for Government Calling supports user-configured features including call forwarding variants, do not disturb, office anywhere, remote office, sequential ring and simultaneous ring. Source: [Webex for Government Calling](https://help.webex.com/en-us/article/n592cco/Webex-for-Government-Calling), supported features table (user-configured). Checked 2026-09-24. [^45]: Webex for Government network requirements list *.webexgov.us among the domains to allow, alongside *.webex.com, *.wbx2.com and *.ciscospark.com. Source: [Network requirements for Webex for Government (FedRAMP)](https://help.webex.com/en-us/article/n71sm9e/Network-requirements-for-Webex-for-Government-(FedRAMP)), domains list. Checked 2026-09-24. [^46]: The What's new in Webex for Government page lists Selective Call Recording (July 2026) and customizable call recording and compliance announcements (March 2026) as additions (disputed). Source: [What's new in Webex for Government](https://help.webex.com/article/ycv8q3/What's-new-in-Webex-for-Government), July 2026 > Selective Call Recording for Compliance & Cost Control; March 2026 > Customizable call recording & compliance announcements. Checked 2026-09-24. [^47]: The What's new in Webex for Government page lists a July 2026 entry for configurable retention for Business Texting (disputed). Source: [What's new in Webex for Government](https://help.webex.com/article/ycv8q3/What's-new-in-Webex-for-Government), July 2026 > Configurable retention for business texting. Checked 2026-09-24. [^48]: The What's new in Webex for Government page lists entries announcing Webex Go availability with Certified Calling Providers and for Wholesale RTM (disputed). Source: [What's new in Webex for Government](https://help.webex.com/article/ycv8q3/What's-new-in-Webex-for-Government), entries 'Webex Go available with Certified Calling Providers' and 'Webex Go availability for Wholesale RTM' (month heading uncertain: January-March 2025). Checked 2026-09-24. [^49]: For Webex for Government only certificate-based trunking on CUBE is supported: registration-based trunking is unavailable and no third-party session border controllers are supported. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Webex for Government note. Checked 2026-09-04. [^50]: Webex for Government requires Cisco IOS XE Dublin 17.12.1a or later on the Local Gateway. Source: [Configure Local Gateway on Cisco IOS XE for Webex Calling](https://help.webex.com/en-us/article/jr1i3r/Configure-Local-Gateway-on-Cisco-IOS-XE-for-Webex-Calling), Webex for Government requirements. Checked 2026-09-04. [^51]: Webex for Government does not support registration-based trunking, and the only Local Gateway platform its certificate-based column marks supported is Cisco Unified Border Element; every third-party session border controller row reads not supported for Webex for Government. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Supported session border controllers introduction, and the Webex for Government column of Table 3 and Table 4. Checked 2026-09-15.