Yes, justonemail.net can receive emails.
No, justonemail.net 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
184.168.221.43
MX records
mailstore1.secureserver.net
72.167.238.32
smtp.secureserver.net
68.178.213.37