A method may include receiving a call placed to a local telephone number and identifying a toll free number associated with the local telephone number. The method may also include determining whether the toll free number is associated with a first call center for a customer using voice over Internet protocol (VoIP) trunking to route calls to the first call center, and identifying a dialed number identification service (DNIS) number associated with the toll free number. The method may further include forwarding the call and the DNIS number to the first call center via a VoIP trunking connection, in response to determining that the toll free number is associated with the first call center.