210-065 · Question #173
A Cisco SX20 is registered to Cisco Unified Communications Manager. It cannot place calls. It is configured with SIP URI 1007 and when traces are run, SIP Forbidden and Unknown calling DN errors are…
The correct answer is D. SIP URI does not contain IP address or hostname. A SIP 403 Forbidden error combined with an Unknown Calling DN trace indicates the SIP URI is malformed because it is missing the required domain, IP address, or hostname suffix.
Question
A Cisco SX20 is registered to Cisco Unified Communications Manager. It cannot place calls. It is configured with SIP URI 1007 and when traces are run, SIP Forbidden and Unknown calling DN errors are found. Which statement describes the problem?
Options
- AThe wrong network IP address is assigned to device.
- BThe ACL is blocking port 5060 from device.
- CH.323 is not configured correctly.
- DSIP URI does not contain IP address or hostname.
How the community answered
(31 responses)- A16% (5)
- B3% (1)
- C6% (2)
- D74% (23)
Why each option
A SIP 403 Forbidden error combined with an Unknown Calling DN trace indicates the SIP URI is malformed because it is missing the required domain, IP address, or hostname suffix.
An incorrect IP address assignment would cause registration failure or unreachability, not a SIP 403 Forbidden with an Unknown Calling DN error that is specific to URI identity resolution.
An ACL blocking port 5060 would prevent all SIP signaling from reaching CUCM entirely, rather than producing a Forbidden response from CUCM that indicates the call was received but rejected.
H.323 configuration is irrelevant here because the device is registered and communicating via SIP, and the error messages returned are SIP-specific protocol responses.
A valid SIP URI must follow the format user@domain or user@ip-address. When only the extension number '1007' is entered without the domain or hostname portion, CUCM cannot resolve the calling party identity. This causes CUCM to return a 403 Forbidden response and log an Unknown Calling DN error because the URI does not match any provisioned directory number format.
Concept tested: SIP URI format requirements for CUCM endpoint registration
Source: https://www.cisco.com/c/en/us/support/collaboration-endpoints/telepresence-sx-series/tsd-products-support-series-home.html
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