SIP 2xx codes are successful responses.
They confirm that the request (like an INVITE, REGISTER, or BYE) has been received, understood, and successfully processed.
Unlike error codes, 2xx responses mean things are going well, but understanding what they signal and how your platform handles them is still important, especially in complex SIP environments.
Make sure your SIP success responses really mean success.
With Voyced’s Premium Plus routing, 2xx codes lead to stable, crystal-clear conversations.
Explore Business VoIP with real results
✅ SIP 2xx Response Codes Explained
200 OK
This is the most common success response. It confirms that a request has succeeded.
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For
INVITE, this means the call has been answered and a session is established. -
For
REGISTER, it confirms successful registration to the SIP server. -
For
BYE, it confirms the session was ended cleanly.
202 Accepted (Deprecated)
This used to mean the request has been accepted for future processing but is not yet complete.
⚠️ It is now deprecated and should no longer be used in current SIP implementations.
204 No Notification
Indicates that the request succeeded, but no reply will be sent back.
It’s rarely used, and not all SIP platforms handle it well.
Most often seen in subscription-based or event-notification systems (e.g., presence updates).
⚠️ Why You Might Still See Issues, Even with a 2xx
While 2xx codes signal success, SIP transactions don’t end there:
-
A
200 OKto anINVITErequires anACKto complete the handshake, missing ACKs can cause dropped calls or 32-second disconnects. -
If multiple 2xx responses are received from forked dialogs, your platform must be able to properly handle multiple confirmed dialogs (RFC 3261 §13.2.2.4).
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Misconfigured firewalls or session timers may still cut off the call even after a
200 OK.
So even success needs to be handled well.
✅ Why Businesses Choose Voyced
Voyced ensures full, reliable support for SIP responses, including all 2xx transactions, with a platform built for professional, international use.
With us, you get:
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Global DIDs in 165+ countries
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A–Z Termination for worldwide outbound calling
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Full RFC-compliant SIP support (with ACKs, dialog handling, SRTP, etc.)
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Secure sessions with optional TLS and SRTP
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Included Hosted IPPBX with voicemail, IVR, and queues
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Premium Plus call routing for reliable CLI and better audio
Whether you need multi-site trunking, flexible Hosted IPPBX options, or reliable failover and presence support, we’ve got the tools in place.
Not all 200 OKs are equal
If you’ve experienced dropped calls, failed registrations, or unreliable SIP behaviour even after getting a 2xx response, your VoIP provider might be the weak link.
Avoid “cheap SIP” pitfalls. Choose a provider that actually knows SIP.
Talk to Voyced
for reliable VoIP services, tested across Europe and beyond.
Last updated: 01/04/2025
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All information provided is copyrighted and purely informative in nature. It is maintained by Voyced with the greatest of care using reliable sources only.
Given the fast evolution of the telecom sector, Voyced does not offer any guarantee about the accuracy and completeness of the information offered.
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