Why spam filters look at links
Sender addresses and IPs can be swapped at will. The domain a spam message links to, however, cannot easily be replaced — that is where whatever the sender wants to sell or harvest actually lives. This is exactly why URI blacklists are among the most effective anti-spam tools, and why filters like SpamAssassin and Rspamd weight a hit here very heavily.
For you as a legitimate sender this means a single problematic link can push an otherwise flawless message into the spam folder — even when SPF, DKIM and DMARC all pass.
What AnalyzeMy.Email checks
- All links from the HTML and text parts of the message are extracted (up to 50)
- The host domain is resolved from every link and deduplicated
- Each domain is queried against URIBL, Spamhaus DBL and SURBL
- Queries run in parallel; the result names both domain and list
Typical triggers for legitimate senders
- URL shorteners: bit.ly, t.co and similar obscure the destination. Some shortener domains are listed wholesale because they are abused at scale. Shorteners have no place in business email.
- Tracking and click domains: newsletter systems rewrite links onto their own redirect domains. If you share that domain with the provider's other customers, you share their reputation too.
- Third-party content: one link to a hacked partner site is enough.
- Image hosts and cloud storage: free file hosts appear on lists far more often than your own domain.
- Stale signatures: linked campaign pages that expired long ago and were re-registered by someone else.
What you can do about it
- Link your own domain instead of shorteners and third-party redirects.
- Configure a dedicated tracking subdomain at your newsletter provider (CNAME to the service) rather than using the shared default domain.
- Review links regularly — especially in signatures and automated mail that runs unchanged for years.
- Link sparingly. A large number of links, particularly across many different domains, is a spam signal in its own right.