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 usa, can. Inferred improvements during Jul 2021: ASN Name Fixed-By 1206 PSCNET-HS 2021-07-20 11427 TWC-11427-TEXAS 2021-07-29 13876 FIBER-64 2021-07-31 Further information for the inferred remediation is available at: https://spoofer.caida.org/remedy.php Source Address Validation issues inferred during Jul 2021: ASN Name First-Spoofed Last-Spoofed 6939 HURRICANE 2016-02-22 2021-07-20 5650 FRONTIER-FRTR 2016-02-22 2021-07-30 577 BACOM 2016-03-09 2021-07-19 209 CENTURYLINK-US-LEGACY-QWEST 2016-08-16 2021-07-28 6128 CABLE-NET-1 2016-09-03 2021-07-09 20412 CLARITY-TELECOM 2016-09-30 2021-07-31 6181 FUSE-NET 2016-10-10 2021-07-30 1403 EBOX 2016-11-12 2021-07-14 22898 ATLINK 2016-12-16 2021-07-30 63296 AWBROADBAND 2017-09-01 2021-07-29 546 PARSONS-PGS-1 2017-11-20 2021-07-14 12222 AKAMAI 2018-02-14 2021-07-22 393564 SPOKANE 2018-06-05 2021-07-27 20448 VPNTRANET-LLC 2018-09-20 2021-07-22 5078 ONENET-AS-1 2020-04-06 2021-07-31 56207 Converge 2021-03-26 2021-07-26 1299 TELIANET 2021-06-02 2021-07-23 22616 ZSCALER-SJC1 2021-07-23 2021-07-23 Further information for these tests where we received spoofed packets is available at: https://spoofer.caida.org/recent_tests.php?country_include=usa,can&no_block=1 Please send any feedback or suggestions to spoofer-info@caida.org