# Link Detection

Control which URLs can be posted in your server using whitelists and blacklists.

## Filtering Modes

- **Blacklist Mode:** All links are allowed except domains you explicitly block. Best for relaxed servers.

- **Whitelist Mode:** All links are blocked except domains you explicitly allow. Best for strict servers.

## Domain Rules

Add domains (e.g. `youtube.com`, `twitter.com`) to your whitelist or blacklist. Subdomains are automatically included unless you specify otherwise.

| Setting | Description |
| --- | --- |
| Subdomain Matching | When enabled, blocking example.com also blocks sub.example.com. |
| Redirect Detection | Follows URL shorteners (bit.ly, t.co) to check the final destination. |
| Embed Suppression | Optionally suppress link embeds for flagged URLs instead of deleting the message. |

> Redirect detection adds a small delay to link processing. Only enable it if link shortener abuse is a problem in your community.