| Date | Domain | IP |
| assets-useast2.postmarkapp.com | 2021-11-19 | 99.84.64.22 |
| rebound.postmarkapp.com | 2023-10-04 | 3.14.57.40 |
| rwd.postmarkapp.com | 2025-10-12 | 161.35.235.194 |
| blog.postmarkapp.com | 2014-06-06 | 66.6.40.74 |
| sg.postmarkapp.com | 2024-11-24 | 18.224.119.155 |
| api.postmarkapp.com | 2023-08-16 | 3.137.63.180 |
| spamcheck.postmarkapp.com | 2024-01-11 | 3.136.198.246 |
| assets.postmarkapp.com | 2024-07-22 | 99.84.66.66 |
| public-assets.postmarkapp.com | 2025-10-13 | 50.31.156.110 |
| craft-assets.postmarkapp.com | 2025-03-09 | 3.163.189.111 |
| status.postmarkapp.com | 2025-08-10 | 146.75.41.91 |
| account.postmarkapp.com | 2024-05-09 | 3.137.63.19 |
| support.postmarkapp.com | 2024-07-12 | 18.216.16.253 |
| public-assets-dev.postmarkapp.com | 2025-10-13 | 50.31.156.110 |
| www.postmarkapp.com | 2023-10-04 | 3.138.237.220 |