Definition
An open relay enables anyone to send email through an email server without authentication. However, this configuration poses a significant security risk as attackers can exploit it to share malicious messages. So, you should configure servers to perform user verification before permitting email transmission.
Open Relay Applications
- Internal communication: An open relay is ideal for a private network. It allows unrestricted email communication between departments or devices, removing the need for user verification.
- Legacy systems integration: Open relay enables integration of older and modern infrastructures that otherwise would be incompatible.
- Testing environments: IT professionals and developers can use open relays in a controlled environment to replicate email flows and troubleshoot potential problems without authentication barriers.
- Temporary connectivity: An open relay can be used in situations that require short-term, urgent email capabilities, such as during specific configurations or migrations.
- Specialized application messaging: Open relay can be used in applications that require sending alerts or notifications through email without the ability to authenticate.