Simple definition
SPF SoftFail Generally corresponds to the ~all mechanism and indicates that an unauthorized source should be treated with caution.
Technical definition
SPF SoftFail Generally corresponds to the ~all mechanism and indicates that an unauthorized source should be treated with caution. In the business environment, its configuration must be consistent with the network architecture, the safety policies and capabilities of the equipment concerned.
What is it used for?
deploy SPF gradually.
Practical example
a domain ends its SPF ~all during a transition phase.
Common issues
- Inconsistent configuration
- Compatibility or version
- Incomplete dependency diagnosis
Key takeaway: Always adapt the diagnosis to the product version and the architecture actually deployed.