1&1
Status:sip.1und1.de is normally a registrar/termination host, not evidence of external FQDN forwarding. No verified global source list is included. Action: confirm product support, sent DID format, and all signaling sources with 1&1.
Plusnet / Fonial
Status: Fonial documents SIP users and trunking, but SIP-URI forwarding is account-dependent.sip.plusnet.de is an outbound host, not an inbound allowlist. Action: configure outbound separately and obtain current forwarding/source details from Fonial.
3CX
Status: a customer-specific FQDN identifies a PBX, not its upstream carrier; sources depend on hosting and NAT. Action: use a supported generic IP trunk, disable registration for FQDN delivery, and allow only verified public PBX/SBC signaling IPs.Localphone
Status: alocalphone.com endpoint alone is not a verified inbound profile. Action: confirm external SIP-URI routing, DID format, transport, and signaling sources with Localphone.
i-pbx
Status: the hostname can identify a PBX or reseller; no global list is verified. Action: identify the actual operator and obtain account-specific public signaling addresses.DIDWW
Status: routing a DID to a SIP URI is supported, but auth and sources follow current account/trunk documentation. Action: use current DIDWW sources; never reuse DIDLogic addresses.Zadarma
Status: credentials and routing are account-specific; no global list is verified here. Action: confirm FQDN forwarding plus documented downstream Digest or current signaling CIDRs.sipcall
Status: capabilities vary by product and region. Action: ask support for external SIP-URI routing, number format, transport, and current sources.Starface
Status: this is a PBX; its public address depends on deployment, SBC, and NAT. Action: route to the platform FQDN and allow only verified static public PBX/SBC addresses.Asterisk / FreePBX
Status: self-managed PBX; no vendor-global list exists. Action: use its static public signaling IP/CIDR, exact DID rewrite, matching TCP/TLS, and separate RTP rules.RingCentral
Status: generic SIP/BYOC depends on the purchased product. Action: confirm external SIP destination support and request current regional signaling ranges.Genesys Cloud
Status: BYOC Cloud uses account/region-specific trunks and edge endpoints. Action: follow the current Genesys BYOC design and only its supplied addresses.Five9
Status: SIP interconnection is an implementation-managed enterprise integration. Action: obtain destination, transport, codecs, auth, and source networks from the Five9 team.Amazon Chime SDK Voice Connector
Status: Voice Connectors use region-specific signaling information. Action: use the current data for the selected AWS region; never reuse another region’s addresses.Aircall
Status: external SIP forwarding/BYOC depends on product and enablement. Action: confirm FQDN delivery and obtain current account sources from Aircall.Placetel
Status: no verified direct external-FQDN profile is documented here. Action: treat it as unsupported until Placetel confirms route, number format, auth, transport, and source ranges in writing.Peoplefone
Status: capabilities and SBC addresses vary by country/product. Action: request the exact external SIP route and regional source networks for the account.NFON
Status: Cloud PBX interconnect is product-controlled; no global list is asserted. Action: use a support-assisted setup and only the destination/source networks supplied by NFON.Sipgate
Status: trunking and forwarding are product-specific; no global list is asserted. Action: confirm external SIP-URI routing and current signaling sources before saving.Voxbi / Mixvoip
Status: these public host classes appeared in legacy saved trunks, but no current first-party provider-to-platform authentication profile was verified. Action: identify the exact product and region, then obtain the current FQDN-routing method and complete signaling sources from the provider or account portal.TeamFON / TeamsIP
Status: these hosted-telephony host classes appeared in legacy saved trunks; a saved hostname or credential mode is not proof of downstream Digest support. Action: confirm the account’s external SIP destination support, DID format, transport, and current public signaling sources.Required confirmation
Ask whether the DID can be delivered to an external FQDN without REGISTER; the exact DID format in the Request-URI; whether the provider authenticates toward the destination with Digest and where those origination credentials are set; otherwise all signaling CIDRs and failover regions; TCP 5060 or TLS 5061; and whether SRTP is required. Only an external call with a platform inbound record, the assigned assistant, and two-way audio confirms the integration. Reject allowlist entries that contain prose, placeholders, hostnames, or unrelated public resolvers such as8.8.8.8. A provider network written without its CIDR prefix is only one host and must not be silently expanded or corrected.
Sources: LiveKit, DIDWW, Fonial, 3CX, Asterisk, Genesys BYOC, Amazon Chime, Zadarma, sipcall, Starface, RingCentral, Five9, Aircall, Placetel, Peoplefone, NFON, Sipgate. Accessed 22 August 2026.