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NAT and STUN: why registered calls can still have no audio

Updated 2026-10-30 · Prepared by Call Global Communications Inc

Short answer: Network Address Translation lets private devices share a public network address. SIP signaling and audio can be affected differently when the receiving side cannot reach the expected address or port.

STUN helps software discover how it appears outside a NAT. Firewall policy, media settings and the chosen client still matter; changing a password will not repair an unreachable audio path.

Use the definition to check your setup

Network Address Translation lets private devices share a public network address. SIP signaling and audio can be affected differently when the receiving side cannot reach the expected address or port.

STUN helps software discover how it appears outside a NAT. Firewall policy, media settings and the chosen client still matter; changing a password will not repair an unreachable audio path.

NAT and STUN: why registered calls can still have no audio — points to check

Review pointCallGlobal guidance
ConceptNetwork Address Translation lets private devices share a public network address. SIP signaling and audio can be affected differently when the receiving side cannot reach the expected address or port.
Configuration implicationSTUN helps software discover how it appears outside a NAT. Firewall policy, media settings and the chosen client still matter; changing a password will not repair an unreachable audio path.
Product boundaryConsult the feature list; a glossary term does not identify an included capability.

Where the CallGlobal line fits

Your number account provides the public telephone identity, its communication controls and the SIP credentials for compatible software. Other capabilities belong to the application or phone system you choose.

Review the live product feature list before relying on an additional function. Number porting, hosted IVR, voicemail, call recording and a public customer API are not included.

Protect the line and the account

  • Keep account and SIP passwords private, including in support screenshots.
  • Confirm the active rental term before relying on incoming communication.
  • Use the complete international number and only an authorized caller identity.

Frequently asked questions

What does this term describe?

Network Address Translation lets private devices share a public network address. SIP signaling and audio can be affected differently when the receiving side cannot reach the expected address or port.

How does this affect practical configuration?

STUN helps software discover how it appears outside a NAT. Firewall policy, media settings and the chosen client still matter; changing a password will not repair an unreachable audio path.

Does every telephone concept name an included product feature?

No. A glossary explains terminology. The product feature page and your number dashboard identify the functions provided with a CallGlobal line.

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