RBLProxy

Posted on: October 30, 2024, 11:23 am

I’m happy to announce RBLProxy, a public DNSBL proxy available at rblproxy.clientnshosting.net. RBLProxy acts as a DNSBL scoring system, a feature missing from most email software. RBLProxy can be used as a single, streamlined solution, replacing the need for multiple individual DNSBLs in your configuration.

Here’s how it works:

When you query rblproxy.clientnshosting.net with an IP address (in reverse format), RBLProxy checks the IP against several reputable DNSBLs like Spamhaus, Spamcop and others. If multiple lists flag the IP, indicating a high-risk consensus, RBLProxy will block it by returning an A record of 127.0.0.2 and a TXT record stating, “IP is blacklisted due to presence on multiple RBLs”. If the IP doesn’t meet the high-risk threshold, the response will show NXDOMAIN, meaning the IP is likely safe.

This scoring approach ensures that only IPs flagged by multiple sources are blocked, which drastically reduces false positives while maintaining strong protection against spam. RBLProxy is free and open for integration with email servers, spam filters, or custom security scripts. It’s super easy to use and highly effective — try it out, and feel free to share your feedback!

Delisting:

If RBLProxy flags an IP, it means that multiple DNSBLs have listed it, indicating suspicious or abusive activity. The administrator of the flagged IP should investigate and resolve the root cause of the abuse (such as spam, malware distribution, or open relays) before seeking removal. To identify which specific blacklists the IP appears on, you can use MultiRBL lookup tools such as:

- https://multirbl.valli.org/

- https://antispamalliance.com/multirbl/

Once the issue is resolved and the listings are cleared, RBLProxy will no longer flag the IP once it falls below the risk threshold.

This is a personal project I developed and am sharing to help make the internet a safer place. It’s provided openly and, of course, as-is.