{"classifier_version":"1.4.0","documentation":"https://rirtracker.com/api/","disclaimer":"This site independently analyzes publicly available Internet number-resource records. It is not affiliated with or endorsed by ARIN, the RIPE NCC, APNIC, LACNIC, AFRINIC, the Number Resource Organization (NRO), or any other Regional Internet Registry. Classifications and hold-expiration dates are evidence-based interpretations and do not constitute confirmation that a resource is available for issuance or transfer.","resource":"131.143.0.0/16","resource_type":"ipv4","page":"https://rirtracker.com/ip/131.143.0.0-131.143.255.255/","statistics_now":{"registry":"ARIN","status":"allocated (111 records, dated 2025-10-06 to 2026-01-13), reserved (1 record)"},"current_holder":{"rir":null,"org":null,"how":null},"rdap_snapshots":[],"transfers":[{"id":43705,"date":"2026-04-29T18:02:09Z","type":"MERGER_ACQUISITION","source_rir":"ARIN","recipient_rir":"ARIN","source_org":"FLOCK SERVICES INC","recipient_org":"Nova Technologies & Investments Inc","range":"131.143.28.0/24","log":"ARIN"}],"events":[{"event_id":"5e60ef7035751526","registry":"ARIN","report_date":"2025-10-06","source":"arin_issued","raw_action":"REMOVE","raw_line":"Remove 131.143.0.0-131.143.255.255","resource_type":"ipv4","resource":"131.143.0.0/16","start":"131.143.0.0","end":"131.143.255.255","classification":"POOL_RECORD_CHANGE","classification_label":"Change to ARIN's own pool record","confidence":"OBSERVED_ONLY","source_rir":null,"recipient_rir":null,"source_organization":null,"recipient_organization":null,"inventory_effect":"Part of the issuance reported the same day","inventory_effect_code":"PAIRED","provisional":false,"classifier_version":"1.4.0","classified_at":"2026-10-13T23:54:35+00:00","page":"https://rirtracker.com/ip/131.143.0.0-131.143.255.255/#e-5e60ef7035751526","report_page":"https://rirtracker.com/arin/reports/2025-10-06/","evidence_url":"https://rirtracker.com/api/v1/resources/ip/131.143.0.0-131.143.255.255.json","explanation":"ARIN's statistics show it reserved on 2025-10-05 and allocated (dated 2025-10-06), available, reserved on 2025-10-07. ARIN removed its own pool record for this range as part of issuing it: the same report adds 131.143.212.0-131.143.215.255, 131.143.220.0-131.143.221.255, 131.143.224.0-131.143.227.255, 131.143.228.0-131.143.231.255 and 13 more. The issuance is explained on those lines. Another change to this range was reported the day before or after (2025-10-07: Add 131.143.16.0-131.143.19.255; 2025-10-07: Add 131.143.20.0-131.143.23.255; 2025-10-07: Add 131.143.24.0-131.143.27.255), so the before-and-after statistics may include it.","evidence":[{"type":"arin_issued","url":"https://lists.arin.net/pipermail/arin-issued/2025-October/006141.html","retrieved_at":"2026-10-12T18:43:11+00:00","summary":"ARIN-Issued report for 2025-10-06: \"Remove 131.143.0.0-131.143.255.255\""},{"type":"delegated_before","url":"https://ftp.arin.net/pub/stats/arin/archive/2025/delegated-arin-extended-20251005.gz","retrieved_at":"2026-10-13T00:08:04+00:00","summary":"ARIN delegated statistics 2025-10-05 (produced 2025-10-05T13:00:49+00:00), before the report: reserved"},{"type":"delegated_after","url":"https://ftp.arin.net/pub/stats/arin/archive/2025/delegated-arin-extended-20251007.gz","retrieved_at":"2026-10-13T00:08:09+00:00","summary":"ARIN delegated statistics 2025-10-07 (produced 2025-10-07T13:00:46+00:00), after the report: allocated (dated 2025-10-06), available, reserved"}]},{"event_id":"b783e73a668d3704","registry":"ARIN","report_date":"2024-11-08","source":"statistics","raw_action":"NOT_IN_ARIN_ISSUED","raw_line":null,"resource_type":"ipv4","resource":"131.143.0.0/16","start":"131.143.0.0","end":"131.143.255.255","classification":"REMOVED_REASON_UNKNOWN","classification_label":"Removed (return, revocation or reclamation not publicly distinguishable)","confidence":"STRONG_INFERENCE","source_rir":null,"recipient_rir":null,"source_organization":null,"recipient_organization":null,"inventory_effect":"Possible future reissue candidate after hold","inventory_effect_code":"HOLD_CANDIDATE","provisional":false,"classifier_version":"1.4.0","classified_at":"2026-10-14T00:12:34+00:00","page":"https://rirtracker.com/ip/131.143.0.0-131.143.255.255/#e-b783e73a668d3704","report_page":"https://rirtracker.com/arin/reports/2024-11-08/","evidence_url":"https://rirtracker.com/api/v1/resources/ip/131.143.0.0-131.143.255.255.json","observed":"131.143.0.0/16 allocated on 2024-11-08, reserved on 2024-11-09","hold":{"hold_rule_source_url":"https://www.arin.net/resources/guide/request/#reissuing-returned-revoked-and-reclaimed-resources","hold_rule_days":60,"estimated_hold_end":"2025-01-07","availability_statement":"Possible reissue candidate after this date; not confirmed available"},"explanation":"Removed from active registration. ARIN-Issued didn't list this; the tracker found it by comparing ARIN's daily statistics. ARIN's statistics show it allocated (dated 1988-11-21) on 2024-11-07 and reserved on 2024-11-09. Public sources do not distinguish a voluntary return, revocation, or reclamation. ARIN holds returned, revoked and reclaimed IPv4 space for 60 days before reissuing it, so the estimated hold end is 2025-01-07. This does not confirm availability.","evidence":[{"type":"statistics_diff","url":"https://ftp.arin.net/pub/stats/arin/archive/2024/delegated-arin-extended-20241109.gz","retrieved_at":"2026-10-12T23:49:39+00:00","summary":"Not listed in ARIN-Issued; found by comparing ARIN's daily statistics: 131.143.0.0/16 allocated on 2024-11-08, reserved on 2024-11-09"},{"type":"delegated_before","url":"https://ftp.arin.net/pub/stats/arin/archive/2024/delegated-arin-extended-20241107.gz","retrieved_at":"2026-10-12T23:49:34+00:00","summary":"ARIN delegated statistics 2024-11-07 (produced 2024-11-07T14:00:51+00:00), before the report: allocated (dated 1988-11-21)"},{"type":"delegated_after","url":"https://ftp.arin.net/pub/stats/arin/archive/2024/delegated-arin-extended-20241109.gz","retrieved_at":"2026-10-12T23:49:39+00:00","summary":"ARIN delegated statistics 2024-11-09 (produced 2024-11-09T14:00:51+00:00), after the report: reserved"}]}],"classification_history":{"5e60ef7035751526":[{"raw_change_id":196306,"classification_code":"POOL_RECORD_CHANGE","confidence":"OBSERVED_ONLY","classifier_version":"1.3.0","classified_at":"2026-10-13T04:07:58+00:00","current":0,"public_explanation":"ARIN's statistics show it reserved on 2025-10-05 and allocated (dated 2025-10-06), available, reserved on 2025-10-07. ARIN removed its own pool record for this range as part of issuing it: the same report adds 131.143.212.0-131.143.215.255, 131.143.220.0-131.143.221.255, 131.143.224.0-131.143.227.255, 131.143.228.0-131.143.231.255 and 13 more. The issuance is explained on those lines. Another change to this range was reported the day before or after (2025-10-07: Add 131.143.16.0-131.143.19.255; 2025-10-07: Add 131.143.20.0-131.143.23.255; 2025-10-07: Add 131.143.24.0-131.143.27.255), so the before-and-after statistics may include it."},{"raw_change_id":196306,"classification_code":"POOL_RECORD_CHANGE","confidence":"OBSERVED_ONLY","classifier_version":"1.3.1","classified_at":"2026-10-13T08:08:06+00:00","current":0,"public_explanation":"ARIN's statistics show it reserved on 2025-10-05 and allocated (dated 2025-10-06), available, reserved on 2025-10-07. ARIN removed its own pool record for this range as part of issuing it: the same report adds 131.143.212.0-131.143.215.255, 131.143.220.0-131.143.221.255, 131.143.224.0-131.143.227.255, 131.143.228.0-131.143.231.255 and 13 more. The issuance is explained on those lines. Another change to this range was reported the day before or after (2025-10-07: Add 131.143.16.0-131.143.19.255; 2025-10-07: Add 131.143.20.0-131.143.23.255; 2025-10-07: Add 131.143.24.0-131.143.27.255), so the before-and-after statistics may include it."},{"raw_change_id":196306,"classification_code":"POOL_RECORD_CHANGE","confidence":"OBSERVED_ONLY","classifier_version":"1.3.2","classified_at":"2026-10-13T14:51:01+00:00","current":0,"public_explanation":"ARIN's statistics show it reserved on 2025-10-05 and allocated (dated 2025-10-06), available, reserved on 2025-10-07. ARIN removed its own pool record for this range as part of issuing it: the same report adds 131.143.212.0-131.143.215.255, 131.143.220.0-131.143.221.255, 131.143.224.0-131.143.227.255, 131.143.228.0-131.143.231.255 and 13 more. The issuance is explained on those lines. Another change to this range was reported the day before or after (2025-10-07: Add 131.143.16.0-131.143.19.255; 2025-10-07: Add 131.143.20.0-131.143.23.255; 2025-10-07: Add 131.143.24.0-131.143.27.255), so the before-and-after statistics may include it."},{"raw_change_id":196306,"classification_code":"POOL_RECORD_CHANGE","confidence":"OBSERVED_ONLY","classifier_version":"1.4.0","classified_at":"2026-10-13T23:54:35+00:00","current":1,"public_explanation":"ARIN's statistics show it reserved on 2025-10-05 and allocated (dated 2025-10-06), available, reserved on 2025-10-07. ARIN removed its own pool record for this range as part of issuing it: the same report adds 131.143.212.0-131.143.215.255, 131.143.220.0-131.143.221.255, 131.143.224.0-131.143.227.255, 131.143.228.0-131.143.231.255 and 13 more. The issuance is explained on those lines. Another change to this range was reported the day before or after (2025-10-07: Add 131.143.16.0-131.143.19.255; 2025-10-07: Add 131.143.20.0-131.143.23.255; 2025-10-07: Add 131.143.24.0-131.143.27.255), so the before-and-after statistics may include it."}],"b783e73a668d3704":[{"raw_change_id":471811,"classification_code":"REMOVED_REASON_UNKNOWN","confidence":"STRONG_INFERENCE","classifier_version":"1.3.0","classified_at":"2026-10-13T06:10:28+00:00","current":0,"public_explanation":"Removed from active registration. ARIN-Issued didn't list this; the tracker found it by comparing ARIN's daily statistics. ARIN's statistics show it allocated (dated 1988-11-21) on 2024-11-07 and reserved on 2024-11-09. Public sources do not distinguish a voluntary return, revocation, or reclamation. ARIN holds returned, revoked and reclaimed IPv4 space for 60 days before reissuing it, so the earliest estimated hold expiration is 2025-01-07. This does not confirm availability."},{"raw_change_id":471811,"classification_code":"REMOVED_REASON_UNKNOWN","confidence":"STRONG_INFERENCE","classifier_version":"1.3.1","classified_at":"2026-10-13T08:23:12+00:00","current":0,"public_explanation":"Removed from active registration. ARIN-Issued didn't list this; the tracker found it by comparing ARIN's daily statistics. ARIN's statistics show it allocated (dated 1988-11-21) on 2024-11-07 and reserved on 2024-11-09. Public sources do not distinguish a voluntary return, revocation, or reclamation. ARIN holds returned, revoked and reclaimed IPv4 space for 60 days before reissuing it, so the earliest estimated hold expiration is 2025-01-07. This does not confirm availability."},{"raw_change_id":471811,"classification_code":"REMOVED_REASON_UNKNOWN","confidence":"STRONG_INFERENCE","classifier_version":"1.3.2","classified_at":"2026-10-13T15:07:18+00:00","current":0,"public_explanation":"Removed from active registration. ARIN-Issued didn't list this; the tracker found it by comparing ARIN's daily statistics. ARIN's statistics show it allocated (dated 1988-11-21) on 2024-11-07 and reserved on 2024-11-09. Public sources do not distinguish a voluntary return, revocation, or reclamation. ARIN holds returned, revoked and reclaimed IPv4 space for 60 days before reissuing it, so the earliest estimated hold expiration is 2025-01-07. This does not confirm availability."},{"raw_change_id":471811,"classification_code":"REMOVED_REASON_UNKNOWN","confidence":"STRONG_INFERENCE","classifier_version":"1.4.0","classified_at":"2026-10-14T00:12:34+00:00","current":1,"public_explanation":"Removed from active registration. ARIN-Issued didn't list this; the tracker found it by comparing ARIN's daily statistics. ARIN's statistics show it allocated (dated 1988-11-21) on 2024-11-07 and reserved on 2024-11-09. Public sources do not distinguish a voluntary return, revocation, or reclamation. ARIN holds returned, revoked and reclaimed IPv4 space for 60 days before reissuing it, so the estimated hold end is 2025-01-07. This does not confirm availability."}]},"arin_statistics_now":{"status":"allocated (111 records, dated 2025-10-06 to 2026-01-13), reserved (1 record)"}}