Yes, giantmail.de can receive emails.
No, giantmail.de 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
217.160.122.95
MX records
mx00.kundenserver.de
212.227.15.41
mx01.kundenserver.de
217.72.192.67