1. A computer-implemented method, comprising: receiving, at an authorizing Domain Name System (DNS) system, a redirected target domain DNS query from a receiving email system, the redirected target domain DNS query generated by the receiving email system based on parsing Sender Policy Framework (SPF) macro statements in a DNS TXT record published at a DNS server of an email domain owner system, the redirected target domain DNS query including identifying information of a delivering email system, the identifying information comprising at least one of an extended HELO (EHLO) name, and an (Internet Protocol) IP address of the delivering email system; extracting the identifying information from the redirected target domain DNS query; determining an identity of the delivering email system from a list of delivering organizations based on the extracted identifying information by accessing a database that associates identifying information with delivering organizations; generating, in response to determining that the identified delivering email system is authorized to deliver email on behalf of the email domain owner system, a DNS record usable in accordance with SPF for indicating that the delivering email system is an authorized sender of email for the email domain owner system; and transmitting the DNS record to the receiving email system.