I whitelisted every ip in all spf records including the ones in cidr notation, however yet yesterday we got an email from an ip not on the list: 18.104.22.168. What gives here? It is tiring to keep having to whitelist numerous ip addresses. ON the list already was 22.214.171.124/30 indicated in sg-warmup.freshemail.io spf record but this didn't include .79. So annoyed at this. Maybe its a larger cidr block I need to whitelist? Please advise!
I resolved this by whitelisting 126.96.36.199/24 . Seems a lot of mailservers send from that subnet. Why no one bothered to reply to this is a bit sad but ok whatever. May want to update the spf record for sg-warmup.freshemail.io?