SPF records
Information about the permissible posts of mail for the domainv=spf1 include:_spf.google.com ip4:40.118.45.62 ip4:185.189.13.6 ip4:185.195.26.219 ip4:147.78.67.21 ip4:185.195.26.90 ip4:185.180.230.155 ip4:185.139.70.142 ip4:147.78.65.7 ~all