> ## Documentation Index
> Fetch the complete documentation index at: https://developers.telnyx.com/llms.txt
> Use this file to discover all available pages before exploring further.

# TLS Requirements

> TLS 1.2 or higher is required for Telnyx SIP and API connections.

Telnyx requires TLS 1.2 or higher for SIP and API connections. TLS 1.0 and TLS 1.1 are not supported.

## Affected services

Use TLS 1.2 or higher for connections to Telnyx domains, including:

* `sip.telnyx.com` and regional SIP domains such as `sip.telnyx.eu`, `sip.telnyx.com.au`, and `sip.telnyx.ca`
* `api.telnyx.com`
* `sms.telnyx.com`
* `lrnlookup.telnyx.com`
* Other `*.telnyx.com` service domains

## SIP clients

Configure SIP clients, PBXs, and SBCs to negotiate TLS 1.2 or higher. For vendor-specific instructions, see [SIP Trunking Configuration Guides](/docs/voice/sip-trunking/configuration-guides).

## API clients

Use current HTTP client and TLS-library versions that negotiate TLS 1.2 or higher by default.