Described herein are methods and systems for enhancing security of transaction requests from POS terminals by utilizing ANI-DNIS information. The header of the transaction request can include automatic source information (“ASI”), which can be extracted from the header by the line handler. The ASI information can be provided to the front end interface, which can compare the ASI information with known customer information. The comparison can provide information indicating whether the transaction is legitimate or fraudulent. If fraudulent, the transaction request can be declined. The ASI information can further be stored in a security analysis database and further queried to identify larger threats including denial of service attacks.