What Is the Difference Between DNIS and ANI?

Dialed Number Information Service (DNIS) and Automatic Number Identification (ANI) are features of the telecommunications network designed to allow telephone users to learn about their connection. Both systems are designed to provide information about a phone number involved in the connection but differ in whether they provide the source phone number, or the original destination number dialed to the recipient.

Dialed Number Information Service (DNIS)

Dialed Number Information Service (DNIS) is designed to allow the recipient of a telephone call the know the phone number originally dialed for an incoming phone call.

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The telecommunications system allows multiple phone numbers to be matched to a single telephone number. The most obvious example of this is 800 numbers within the United States. No organization is actually assigned an 800 number as their phone number; these are numbers that organizations can sign up for via a “Responsible Organization” (or RespOrg) to have forwarded to their traditional number.

The primary use of 800 numbers is for customer service, and many organizations register multiple different forwarding numbers in order to easily sort phone calls. For example, multinational or multilingual organizations may have multiple different phone numbers that map to the same organizational phone number.

When a user calls the organization using one of their phone numbers, the organization can use DNIS to direct the call to the correct recipient. If a user calls the organization’s “Spanish language” number, then the organization can route the call to one of their Spanish-speaking customer service agents.

DNIS can also be used to help improve security against social engineering attacks. An organization can advertise one number internally and another externally and route them to the same phone. Based on the number that is originally dialed, the organization can warn the recipient if this is likely to be a “trusted” (Read more...)

*** This is a Security Bloggers Network syndicated blog from InfoSec Resources authored by Chris Sienko. Read the original post at: