| 12.0.0.0/8 | BGP route | AS7018 AT&T Enterprises, LLC | — |
| 12.0.0.0/8 | WHOIS (ARIN) | AT&T Enterprises, LLC | US |
| 12.0.0.0/8 | ARIN assigned | — | US |
| 12.0.0.0/9 | BGP route | AS7018 AT&T Enterprises, LLC | — |
| 12.80.0.0/12 | BGP route | AS7018 AT&T Enterprises, LLC | — |
| 12.112.0.0/12 | BGP route | AS7018 AT&T Enterprises, LLC | — |
| 12.56.0.0/13 | BGP route | AS7018 AT&T Enterprises, LLC | — |
| 12.112.0.0/13 | WHOIS (ARIN) | AT&T IP Team | US |
| 12.76.0.0/14 | BGP route | AS7018 AT&T Enterprises, LLC | — |
| 12.80.0.0/14 | WHOIS (ARIN) | AT&T Worldnet Services | US |
| 12.56.0.0/15 | WHOIS (ARIN) | AT&T Services, Inc. | US |
| 12.66.0.0/15 | WHOIS (ARIN) | AT&T IP Team | — |
| 12.72.0.0/15 | WHOIS (ARIN) | AT&T Worldnet Services | US |
| 12.78.0.0/15 | WHOIS (ARIN) | AT&T IP Team | US |
| 12.84.0.0/15 | WHOIS (ARIN) | AT&T Worldnet Services | US |
| 12.86.0.0/15 | WHOIS (ARIN) | AT&T IP Team | US |
| 12.90.0.0/15 | WHOIS (ARIN) | AT&T IP Team | US |
| 12.92.0.0/15 | WHOIS (ARIN) | AT&T Worldnet Services | US |
| 12.122.0.0/15 | WHOIS (ARIN) | AT&T Worldnet Services | US |
| 12.55.0.0/16 | BGP route | AS7018 AT&T Enterprises, LLC | — |
| 12.55.0.0/16 | WHOIS (ARIN) | AT&T IP Team | US |
| 12.65.0.0/16 | WHOIS (ARIN) | AT&T Global Services | US |
| 12.74.0.0/16 | WHOIS (ARIN) | AT&T Worldnet Services | US |
| 12.75.0.0/16 | WHOIS (ARIN) | AT&T Worldnet Services | US |
| 12.76.0.0/16 | WHOIS (ARIN) | AT&T IP Team | US |
| 12.77.0.0/16 | WHOIS (ARIN) | AT&T IP Team | US |
| 12.120.0.0/16 | WHOIS (ARIN) | AT&T Worldnet Services | US |
| 12.127.0.0/16 | WHOIS (ARIN) | AT&T IP Team | — |
| 12.64.0.0/17 | WHOIS (ARIN) | AT&T Global Services | US |
| 12.72.0.0/17 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.72.128.0/17 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.73.0.0/17 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.63.0.0/18 | WHOIS (ARIN) | Private Customer | US |
| 12.64.128.0/18 | WHOIS (ARIN) | AT&T Global Services | US |
| 12.73.64.0/18 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.102.192.0/18 | WHOIS (ARIN) | AT&T Services, Inc. | US |
| 12.114.192.0/18 | BGP route | AS17258 AT&T Enterprises, LLC | — |
| 12.115.128.0/18 | BGP route | AS17348 FULL SPECTRUM COMMUNICATIONS, INC. | — |
| 12.121.128.0/18 | WHOIS (ARIN) | AT&T Worldnet Services | US |
| 12.121.192.0/18 | WHOIS (ARIN) | AT&T Worldnet Services | US |
| 12.11.192.0/19 | WHOIS (ARIN) | AT&T Services, Inc. | US |
| 12.64.224.0/19 | WHOIS (ARIN) | AT&T Global Services | US |
| 12.72.0.0/19 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.72.192.0/19 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.73.0.0/19 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.73.32.0/19 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.121.96.0/19 | WHOIS (ARIN) | AT&T Worldnet Services | US |
| 12.12.96.0/20 | WHOIS (ARIN) | NET3 INC | US |
| 12.12.112.0/20 | WHOIS (ARIN) | NET3 INC | US |
| 12.17.176.0/20 | BGP route | AS397602 BOREALIS BROADBAND INC. | — |
| 12.56.0.0/20 | WHOIS (ARIN) | Cometa Networks | US |
| 12.58.16.0/20 | WHOIS (ARIN) | DEPROD_pool LV8N2 | US |
| 12.58.32.0/20 | WHOIS (ARIN) | DEPROD_pool LVP8N3 | US |
| 12.58.48.0/20 | WHOIS (ARIN) | DEPROD_pool LVP8N4 | US |
| 12.58.80.0/20 | WHOIS (ARIN) | DEPROD_pool LVP8N6 | US |
| 12.58.96.0/20 | WHOIS (ARIN) | DEPROD_pool LVP8N7 | US |
| 12.58.112.0/20 | WHOIS (ARIN) | DEPROD_pool LVP8N8 | US |
| 12.58.144.0/20 | WHOIS (ARIN) | DEPROD_pool LVP8N10 | US |
| 12.58.160.0/20 | WHOIS (ARIN) | DEPROD_pool LVP8N11 | US |
| 12.58.176.0/20 | WHOIS (ARIN) | DEPROD_pool LVP8N12 | US |
| 12.58.208.0/20 | WHOIS (ARIN) | DEPROD_pool LVP8N14 | US |
| 12.58.224.0/20 | WHOIS (ARIN) | DEPROD_pool LVP8N15 | US |
| 12.58.240.0/20 | WHOIS (ARIN) | DEPROD_pool LVP8N16 | US |
| 12.59.16.0/20 | WHOIS (ARIN) | DEPROD_pool LV9N2 | US |
| 12.59.32.0/20 | WHOIS (ARIN) | DEPROD_pool LVP9N3 | US |
| 12.59.80.0/20 | WHOIS (ARIN) | DEPROD_pool LVP9N6 | US |
| 12.59.112.0/20 | WHOIS (ARIN) | DEPROD_pool LVP9N8 | US |
| 12.59.128.0/20 | WHOIS (ARIN) | DEPROD_pool LVP9N9 | US |
| 12.59.160.0/20 | WHOIS (ARIN) | DEPROD_pool LVP9N11 | US |
| 12.72.160.0/20 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.72.224.0/20 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.13.40.0/21 | BGP route | AS32869 Silver Star Telecom, LLC | — |
| 12.19.88.0/21 | BGP route | AS109 CISCO SYSTEMS, INC. | — |
| 12.27.240.0/21 | BGP route | AS2727 Electric Plant Board of the City of Glasgow, Kentucky | — |
| 12.36.232.0/21 | BGP route | AS2727 Electric Plant Board of the City of Glasgow, Kentucky | — |
| 12.46.168.0/21 | BGP route | AS8161 Insight Direct USA, Inc. | — |
| 12.72.32.0/21 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.72.40.0/21 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.72.48.0/21 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.72.56.0/21 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.72.104.0/21 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.72.136.0/21 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.72.144.0/21 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.72.240.0/21 | BGP route | AS20057 AT&T Enterprises, LLC | — |
| 12.105.48.0/21 | BGP route | AS54690 California Lutheran University | — |
| 12.0.0.0/22 | BGP route | AS6269 AT&T Enterprises, LLC | — |
| 12.3.80.0/22 | BGP route | AS10998 Bank of America, National Association | — |
| 12.9.136.0/22 | BGP route | AS14990 Avnet Inc. | — |
| 12.12.0.0/22 | BGP route | AS32328 Alascom, Inc. | — |
| 12.14.232.0/22 | BGP route | AS394867 Velocity Communications, Inc. | — |
| 12.18.96.0/22 | BGP route | AS17064 TISD, Inc. | — |
| 12.22.96.0/22 | BGP route | AS2386 AT&T Enterprises, LLC | — |
| 12.22.152.0/22 | BGP route | AS26380 MasterCard Technologies LLC | — |
| 12.22.188.0/22 | BGP route | AS54809 MCM Systems, LLC | — |
| 12.24.4.0/22 | BGP route | AS2727 Electric Plant Board of the City of Glasgow, Kentucky | — |
| 12.27.240.0/22 | BGP route | AS2727 Electric Plant Board of the City of Glasgow, Kentucky | — |
| 12.27.244.0/22 | BGP route | AS2727 Electric Plant Board of the City of Glasgow, Kentucky | — |
| 12.31.224.0/22 | BGP route | AS33331 Valid USA | — |
| 12.32.224.0/22 | BGP route | AS2386 AT&T Enterprises, LLC | — |
| 12.35.188.0/22 | BGP route | AS53768 Laboratory Corporation of America | — |
| 12.38.168.0/22 | BGP route | AS7018 AT&T Enterprises, LLC | — |