| Date | IP Address |
| 2024-05-28 | 3.10.159.92 (ClassC) |
| 2024-12-27 | 3.11.121.12 (ClassC) |
| 2025-02-26 | 18.168.80.190 (ClassC) |
| 2025-03-04 | 18.175.35.237 (ClassC) |
| 2025-05-08 | 13.42.153.47 (ClassC) |
| 2025-06-04 | 18.169.96.81 (ClassC) |
| 2025-07-07 | 18.132.224.119 (ClassC) |
| 2025-08-31 | 13.134.32.163 (ClassC) |
| 2025-09-13 | 13.134.16.180 (ClassC) |
| 2026-01-16 | 3.11.111.64 (ClassC) |
| Date | Domain | IP |
| api.de-sina3.communications.national.nhs.uk | 2026-01-02 | 35.176.137.250 |
| govuknotify.de-sina3.communications.national.nhs.uk | 2024-05-30 | 13.43.187.93 |
| api.de-jara8.communications.national.nhs.uk | 2024-05-30 | 13.43.158.227 |
| apimmock.dev-base.communications.national.nhs.uk | 2025-06-01 | 18.171.139.121 |
| api.dev-nhsapp.communications.national.nhs.uk | 2024-12-27 | 3.11.121.12 |
| api.uat-letters.communications.national.nhs.uk | 2024-05-30 | 35.178.121.74 |
| govuknotify.uat-letters.communications.national.nhs.uk | 2024-05-30 | 13.42.117.209 |