Abstract
Forward-confirmed reverse DNS (FCrDNS) (also known as iprev), considered as client authenticity validation, is an early anti-spam effort to thwart spammers. Over time, anti-forgery techniques evolved with the advent of standards such as the Sender Policy Framework (SPF). SPF includes a ptr mechanism that encompasses an FCrDNS check. In this paper, we characterize the deployment of FCrDNS on prospective senders in practice, study to which extent iprev and SPF ptr checks are performed by large email providers on the receiving side, and how (non)compliance with FCrDNS affects email delivery. Our results show that two-thirds of the prospective senders with PTR record are FCrDNS-configured and that not all large providers strictly require iprev authentication. Our email campaigns show that large email providers exhibit different treatments of the SPF ptr mechanism, possibly because the SPF standard lacks clarity.
| Original language | English |
|---|---|
| Title of host publication | Network Traffic Measurement and Analysis Conference 2025 (TMA'2025) |
| Publisher | IEEE |
| Number of pages | 11 |
| ISBN (Electronic) | 978-3-903176-74-4 |
| Publication status | Published - 10 Jun 2025 |
| Event | 9th Network Traffic Measurement and Analysis Conference, TMA 2025 - Aalborg University, Copenhagen, Denmark Duration: 10 Jun 2025 → 13 Jun 2025 Conference number: 9 https://tma.ifip.org/2025/ |
Conference
| Conference | 9th Network Traffic Measurement and Analysis Conference, TMA 2025 |
|---|---|
| Abbreviated title | TMA 2025 |
| Country/Territory | Denmark |
| City | Copenhagen |
| Period | 10/06/25 → 13/06/25 |
| Internet address |
Keywords
- security
- dns