If a mail server or filtering tool is still referencing the SORBS blacklist, it's worth knowing that SORBS (Spam and Open Relay Blocking System) officially ceased operations in June 2024. Here's what that means in practice and what to do if you still seem to be affected.
What SORBS was
SORBS was a DNS-based real-time blacklist that flagged IP addresses and domains suspected of sending spam or engaging in other malicious activity. It categorized listings into several types, including general spam sources, open mail relays, servers compromised by malware or trojans, dynamic/residential IP ranges, and IPs generating unusual volumes of bounce messages.
Why you might still be affected despite the shutdown
Because SORBS is no longer maintained or updated, it can't generate new listings. However, some mail servers and spam filters run on older configurations that still reference cached or legacy SORBS data. If a server checks a stale local copy of SORBS data rather than querying it live, your IP could still appear "listed" even though the service itself is offline.
How to check
The original SORBS lookup (dnsbl.sorbs.net) may no longer be reliably available since the shutdown. A more practical approach is to run a general blacklist check using a tool like MXToolbox or MultiRBL, which will show you whether SORBS-related entries still appear in any results, and more importantly, whether you're listed on any blacklists that are actively maintained today.
What to do if delivery still seems affected
Since there's no active SORBS team to process a removal request, focus on the fundamentals that determine deliverability regardless of any specific blacklist:
- Confirm SPF, DKIM, DMARC, and reverse DNS (PTR) records are all correctly configured for your sending IP
- Clean your recipient list — remove invalid, bounced, and long-inactive addresses
- If a specific partner or customer isn't receiving your mail, ask their IT team to check whether their filtering system still references outdated SORBS data, and request they whitelist your domain or IP if so
- Check current, actively maintained blacklists (Spamhaus, SpamCop, Barracuda) to rule out a separate, unrelated listing
The lasting lesson from SORBS
Even though the list itself is gone, the standards it enforced haven't changed: clean sending practices, proper authentication, and healthy list hygiene remain the baseline for staying off any blacklist, past or present.
Frequently asked questions
Can I still request removal from SORBS? No — the service is no longer operated or maintained, so there's no active process to submit a request to.
Should I worry about SORBS today? Only indirectly, if a mail server you're sending to happens to rely on stale cached data. Focus your effort on currently active blacklists and general deliverability hygiene instead.
