Question and response
Question
dig spf.realsender.com. A
Answer
spf.realsender.com. 300 A 139.162.190.42
spf.realsender.com. 300 A 172.232.217.127
spf.realsender.com. 300 A 45.56.94.37
Authority
spf.realsender.com. 172800 NS ns-1257.awsdns-29.org.
spf.realsender.com. 172800 NS ns-1640.awsdns-13.co.uk.
spf.realsender.com. 172800 NS ns-412.awsdns-51.com.
spf.realsender.com. 172800 NS ns-854.awsdns-42.net.
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0