This article describes the usage of DNC feature, fully available since 4.4 version of Sippy.

Do Not Call List feature allows adding the list with the numbers (CLDs) that should never be reached through your vendors.

Feature is commonly used in North America region.

1. To be able to use this feature you need to send the request to our support team, so that the request is resent to the billing department of Sippy.

2. Once the module is added, go to DNC List menu under the Routing section to upload the DNC list and upload the file with DNC numbers.

Supported format for DNC list is txt only.

Only solid numbers are supported, without any separation (no comma separation).

Any non-numerical characters are not counted towards number of digits, so that both 123,45678901 and 12345678901 would be considered as 10-digit number 12345678901.

The txt file should NOT have BOM (Byte Order Mark) at the beginning.

Make sure that the numbers you place in DNC file are exactly the numbers your customers might be sending the calls to.

Example: If your customers dial 12345678901 number that you want to be banned for them, you should add this number in full, with leading 1:


3. Once the file is taken for upload, wait for the upload to finish, if the file was uploaded successfully, the Uploaded On date should be changed accordingly.

4. For accounts that you want to restrict CLDs using this DNC list on Accounts details set the checkbox DNCL Lookup 

5. The calls for those accounts to the numbers from DNC list would be dropped with SIP/2.0 470 Consent Needed result

Call processing:

1. Authenticate incoming call either to Incoming DID or to the authentication rule of an account, or using the digest credentials of the account.
2. Apply the number translation if configured on DID pool for call authenticated to Incoming DID
3. Apply the number translation if configured on authentication rule of an account for call authenticated to authentication rule of an account
4. Apply the translation rule of the account
5. Check the resulting translated number in DNCL if DNCL lookup is configured for account that has been authenticated for that call
6. If no match is found, perform LRN lookup and process the call further