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 Dec 2023: ASN Name Fixed-By 207176 OPENFIBER 2023-12-06 Further information for the inferred remediation is available at: https://spoofer.caida.org/remedy.php Source Address Validation issues inferred during Dec 2023: ASN Name First-Spoofed Last-Spoofed 20847 PREVIDER 2018-04-17 2023-12-28 213268 2020-12-07 2023-12-30 207176 OPENFIBER 2022-09-30 2023-12-23 12414 NL-SOLCON 2023-05-22 2023-12-11 28685 ASN-ROUTIT 2023-08-23 2023-12-05 60528 ASN-XANTOS 2023-10-31 2023-12-26 62353 ASN-DATAPLACE 2023-12-12 2023-12-12 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