In response to feedback from operational security communities, CAIDA's source address validation measurement project (https://spoofer.caida.org) is automatically generating monthly reports of ASes originating prefixes in BGP for systems from which we received packets with a spoofed source address. We are publishing these reports to network and security operations lists in order to ensure this information reaches operational contacts in these ASes. This report summarises tests conducted within nld. Inferred improvements during Apr 2021: none inferred Source Address Validation issues inferred during Apr 2021: ASN Name First-Spoofed Last-Spoofed 1136 KPN 2019-09-04 2021-04-29 8587 Infracom 2019-10-28 2021-04-28 213268 Cloudwebservices 2020-12-07 2021-04-29 207375 FIBO 2021-02-19 2021-04-28 Further information for these tests where we received spoofed packets is available at: https://spoofer.caida.org/recent_tests.php?country_include=nld&no_block=1 Please send any feedback or suggestions to spoofer-info@caida.org