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 May 2019: ASN Name Fixed-By 58329 RACKPLACE 2019-05-07 Further information for the inferred remediation is available at: https://spoofer.caida.org/remedy.php Source Address Validation issues inferred during May 2019: ASN Name First-Spoofed Last-Spoofed 12222 AKAMAI 2018-02-14 2019-05-23 28878 SIGNET 2018-06-27 2019-05-27 47886 EQUINIX-NL-ASN 2018-08-09 2019-05-24 16243 VIRTU 2018-08-09 2019-05-24 8737 PT 2019-01-16 2019-05-05 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