Here's how to let Snaglist through the firewall with Wordfence, Cloudflare and Imunify.
Snaglist introduces itself properly on every site with this user-agent:
Mozilla/5.0 (compatible; Snaglist/1.0; +https://snaglist.eu/bot)
Still, some firewalls see a crawler that fetches many pages in a row as an attack. They may start blocking requests after a while. Whitelist Snaglist to prevent this.
In WordPress: Go to Wordfence, Firewall, Firewall Options. Add Snaglist’s IP address to the allowed IP addresses.
In the domain dashboard: Navigate to Security, WAF, Tools. Create an IP Access Rule with Snaglist’s IP address and select Allow.
In cPanel or DirectAdmin: Open Imunify360, Firewall. Whitelist Snaglist’s IP address.
Snaglist crawls from 178.105.130.16. Restart the crawl afterwards.