| Date | IP Address |
| 2019-12-31 | 52.6.60.122 (ClassC) |
| 2024-06-03 | 44.207.80.202 (ClassC) |
| 2024-07-06 | 34.225.74.173 (ClassC) |
| 2024-08-14 | 52.72.231.198 (ClassC) |
| 2024-12-26 | 34.192.86.186 (ClassC) |
| 2025-01-12 | 3.217.14.70 (ClassC) |
| 2025-01-21 | 3.225.174.107 (ClassC) |
| 2025-04-27 | 3.209.48.57 (ClassC) |
| 2025-06-20 | 3.222.87.55 (ClassC) |
| 2025-07-02 | 52.200.163.14 (ClassC) |
| 2025-07-18 | 204.236.236.174 (ClassC) |
| 2025-07-31 | 44.213.15.236 (ClassC) |
| 2025-11-17 | 45.60.11.203 (ClassC) |
| Date | Domain | IP |
| curiousgeorge-v1.int.webnp.hmhco.com | 2024-08-07 | 54.82.51.61 |
| hmhco-v1.int.webnp.hmhco.com | 2024-08-07 | 52.2.104.230 |
| api-consumer-v1.int.webnp.hmhco.com | 2024-08-07 | 54.82.51.61 |
| cliffsnotes-v1.int.webnp.hmhco.com | 2024-08-07 | 52.2.104.230 |
| subscriptions-v1.int.webnp.hmhco.com | 2024-08-07 | 52.2.104.230 |
| api-subscriptions-v1.int.webnp.hmhco.com | 2024-08-07 | 54.82.51.61 |
| admin-subscriptions-v1.int.webnp.hmhco.com | 2024-08-07 | 52.2.104.230 |
| gomathacademy-v1.int.webnp.hmhco.com | 2024-08-07 | 54.82.51.61 |
| web-delivery-v1.int.webnp.hmhco.com | 2025-08-04 | 18.235.151.113 |
| hmhco-v2.int.webnp.hmhco.com | 2024-08-07 | 54.82.51.61 |
| hmhco-v1.cert.webnp.hmhco.com | 2025-10-30 | 54.166.166.198 |
| gomathacademy-v1.cert.webnp.hmhco.com | 2025-08-10 | 45.60.11.203 |
| web-delivery-v1.cert.webnp.hmhco.com | 2024-06-03 | 44.207.80.202 |
| cliffsnotes-v1.dev.webnp.hmhco.com | 2024-08-09 | 44.209.124.240 |
| gomathacademy-v1.dev.webnp.hmhco.com | 2025-04-11 | 34.231.11.210 |
| web-delivery-int.dev.webnp.hmhco.com | 2025-08-10 | 54.167.13.139 |