Yes, dyndns.org can receive emails.
No, dyndns.org is a throwaway domain and should be blocked.
You can use MailCheck's free API to automatically block throwaway emails. Read our documentation to get started. No registration required.
A record
162.88.175.4
MX records
ALT1.ASPMX.L.GOOGLE.COM
64.233.186.27
ALT2.ASPMX.L.GOOGLE.COM
74.125.193.26
ASPMX.L.GOOGLE.COM
173.194.205.26
ASPMX2.GOOGLEMAIL.COM
64.233.186.27
ASPMX3.GOOGLEMAIL.COM
74.125.193.26