A/AAAA IPv6 Record in SPF
TL;DR In v=spf1 a mx ~all the a is for both A (IPv4) and AAAA (IPv6)
Source: http://www.openspf.org/SPF_Record_Syntax
TL;DR In v=spf1 a mx ~all the a is for both A (IPv4) and AAAA (IPv6)
Source: http://www.openspf.org/SPF_Record_Syntax