SIP 483 Too Many Hops

What SIP 483 means

The call was passed along so many times that a safety counter ran out, which almost always means a forwarding loop. Follow the divert chain and you will find two destinations pointing at each other.

Client error (4xx)
Sent by A proxy that saw the hop counter reach zero
Occasional

What SIP 483 Too Many Hops actually means

Each server that handles a request decrements a hop counter, and when it reaches zero the request is rejected rather than allowed to circulate forever. It is a loop protection mechanism, so seeing it means the protection did its job and there is a genuine loop to find.

What causes SIP 483 on a business phone system

Two extensions forward to each otherThe textbook loop: A diverts to B while B diverts to A. It often appears when someone sets a temporary divert and a colleague does the same in the other direction.
A hunt group includes a member that points back into the groupA group member whose own no-answer rule returns the call to the group creates a loop that only triggers when nobody answers, so it survives testing.
An out-of-hours rule points at a daytime rule that points backTime-based routing that references itself through another rule produces a loop that only exists at certain hours.

How to fix SIP 483

Map every forward on the extensions involvedList the divert, busy-forward and no-answer destination for each extension in the chain. Written down, the loop is usually obvious within a few entries.
Check for diverts set on the handset as well as the platformA forward configured on the phone itself does not appear in the platform view, which is why loops can seem impossible from the portal alone.
Give every branch a terminating destinationEnd each chain at voicemail or an announcement rather than at another extension, so a loop cannot form.

Fixing the underlying problem

This page explains the code. These guides walk through the fix in detail.

Questions about SIP 483

What causes SIP 483 Too Many Hops?

A forwarding loop, in nearly every real case. Two extensions diverting to each other, or a hunt group member that sends unanswered calls back to the group, will circulate a call until the hop counter runs out. Map the diverts on each extension in the chain and the loop shows itself.

Related SIP response codes

Source. SIP 483 Too Many Hops is defined in RFC 3261 section 21.4.21 and registered in the IANA SIP Parameters — Response Codes. The causes and fixes above are drawn from our own experience supporting UK business phone systems.

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