SPF records
Information about the permissible posts of mail for the domainv=spf1 ip4:92.53.116.0/22 ip4:92.53.96.0/22 ip4:92.53.112.0/22 ip4:92.53.104.0/22 ip4:46.229.215.58 include:spf.retailcrm.pro include:spf.unisender.com include:_spf.yandex.net ~all