How do I use Do Not Originate with Sinch Elastic SIP Trunking?

Do Not Originate (DNO) is a feature that allows a Sinch Elastic SIP Trunk customer to designate numbers to be one way inbound only. This applies to DID and Toll-Free numbers. This prevents the selected numbers from being able to make outbound calls.

Note: DNO is only available for North American phone numbers.

A Do Not Originate (DNO) list is essentially a blocklist of telephone numbers that should never be used to make outbound calls. If a call appears to come from a number on this list, it is almost certainly fraudulent or "spoofed" and should be blocked.

By maintaining a DNO list, service providers can automatically flag and block calls from these numbers, preventing them from ever reaching a consumer.

Prior to any setup or routing of call, the network will first verify if the originating number is allowed to make a call. If not, call will be immediately rejected with:

Recording:  “Sorry, but your call cannot be completed” SIP 603 (ISUP 21)

This can/should result in elimination of illegal robocall activity through the network if it is coming from numbers that have subscribed to DNO through any participating entity or an invalid number and Elimination of invalid formatting of calls through the network.

By subscribing numbers to the Sinch DNO list, the numbers will be entered into multiple DNO databases as follows:

• Somos RealNumber DNO
• US Telecom Industry Traceback Group
• Neustar
• YouMail
• Sinch Voice Customers
• Sinch Voice Reserve Inventory

How to Add or Remove Numbers to and from the DNO List

Create a support ticket. The authorized user on the account must be the individual who needs to make the request.