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 2019: ASN Name Fixed-By 2828 XO-AS15 2019-07-12 Further information for the inferred remediation is available at: https://spoofer.caida.org/remedy.php Source Address Validation issues inferred during Jul 2019: ASN Name First-Spoofed Last-Spoofed 6939 HURRICANE 2016-02-22 2019-07-27 577 BACOM 2016-03-09 2019-07-06 209 CENTURYLINK-US-LEGACY-QWEST 2016-08-16 2019-07-31 6128 CABLE-NET-1 2016-09-03 2019-07-30 27364 ACS-INTERNET 2016-09-27 2019-07-25 20412 CLARITY-TELECOM 2016-09-30 2019-07-29 6181 FUSE-NET 2016-10-10 2019-07-27 25787 ROWE-NETWORKS 2016-10-21 2019-07-27 32440 LONI 2016-11-03 2019-07-26 2828 XO-AS15 2016-11-08 2019-07-29 12083 WOW-INTERNET 2016-11-09 2019-07-29 13427 SOFTCOM-INTERNET-COMMUNICATION 2016-11-14 2019-07-31 21832 KELLINCOM-1 2017-02-03 2019-07-31 18451 LESNET 2017-02-22 2019-07-23 26253 SCINTERNET 2017-06-30 2019-07-08 63296 AMARILLO-WIRELESS 2017-09-01 2019-07-25 546 PARSONS-PGS-1 2017-11-20 2019-07-30 54540 INCERO 2018-01-15 2019-07-29 12222 AKAMAI 2018-02-14 2019-07-10 4201 ORST 2018-04-19 2019-07-30 225 VIRGINIA 2018-06-18 2019-07-30 33452 RW 2018-09-19 2019-07-28 20448 VPNTRANET-LLC 2018-09-20 2019-07-25 393437 KLAYER 2018-12-21 2019-07-17 63275 RADIOWIRE 2019-02-07 2019-07-31 8047 GCI 2019-04-11 2019-07-31 10745 ARIN-ASH-CHA 2019-04-29 2019-07-25 6058 NORTHWESTEL-INC 2019-05-06 2019-07-31 46573 AS-GLobalf 2019-05-16 2019-07-01 138576 2019-05-21 2019-07-27 19751 CCRTC 2019-06-06 2019-07-29 33387 DATASHACK 2019-06-06 2019-07-26 16787 CHARTER-16787 2019-06-17 2019-07-29 29933 OFF-CAMPUS-TELECOMMUNICATIONS 2019-07-15 2019-07-15 36728 EMERYTELCOM 2019-07-26 2019-07-26 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