| Date | IP Address |
| 2019-12-24 | 104.112.202.173 (ClassC) |
| 2023-08-25 | 23.195.237.25 (ClassC) |
| 2024-09-21 | 184.26.148.126 (ClassC) |
| 2024-12-14 | 95.101.160.246 (ClassC) |
| 2025-06-25 | 23.195.237.30 (ClassC) |
| 2025-07-03 | 184.25.247.198 (ClassC) |
| 2025-08-01 | 104.90.248.54 (ClassC) |
| Date | Domain | IP |
| image.email.citibank.com.hk | 2024-09-21 | 23.198.170.119 |
| click.email.citibank.com.hk | 2025-07-01 | 13.111.18.12 |
| image.uat.email.citibank.com.hk | 2023-08-25 | 23.195.237.25 |
| click.uat.email.citibank.com.hk | 2025-06-25 | 13.111.18.12 |