

| Feature | Greylisting | Blocklisting |
|---|---|---|
| Objective | Delay emails to filter out spam | Block emails from known spammers |
| Delivery Method | Temporary rejection with retries | Permanent rejection with no retries |
| Effect on Email | Delays initial delivery | Prevents all delivery |
| Impact on Reputation | Delayed reputation building | Negative reputation if listed |
| Application Scope | Mainly on new IPs/domains | Known spammers, high-risk IPs/domains |
Clearout deploys breakthrough anti-greylisting technology
Clearout’s anti-greylisting algorithm can determine the real status of email addresses without compromising on the turnaround time. The anti-greylisting process may take a little more time than usual but it increases the number of valid emails and reduces the ‘unknowns’ in the result, making the extra time worth it.
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