
Open Mail Relays are a now old method by which a spammer can send out spam without using his own server.
| How to prevent unauthorized third-party mail relaying through your servers. | |
| Filtering open relays can help to slightly reduce your spam load. | |
| Tools to test for open relays. | |
| Honeypots can be used to trap a spammer in the act of abusing an open relay. |