554 blocked using Barracuda Reputation: IP listed

What it means

Barracuda runs the Barracuda Reputation Block List (BRBL), a DNS blocklist of IPs that have sent spam, queried at b.barracudacentral.org. Barracuda’s own email gateways use it by default, and many other mail servers query it as one of their DNSBLs. When your connecting IP is listed, they refuse the session with this 554 and usually a link to Barracuda’s lookup page.

The refusal is about the IP only. It arrives before your message is read, so no change to content, SPF, or DKIM will move it. Expect the same bounce at every recipient that uses Barracuda products or the BRBL.

Compare it with “550 permanent failure for one or more recipients”, which a Barracuda gateway sends after scanning the message, and with Spamhaus or other DNSBL rejections, which name a different list.

Likely causes

• Spam sent from your IP by a compromised account, a hacked website, or malware on a workstation behind NAT.
• Mail to Barracuda spam traps, often from old purchased or scraped lists.
• No reverse DNS or a generic PTR name on the IP, which makes a listing more likely and removal harder.
• Sharing a NAT or proxy IP with machines you do not control, such as a guest network.

Checks that apply

• Blacklist Check Queries the BRBL and 39 other DNSBLs for the IP, so you see whether Barracuda is the only list involved.
• Reverse DNS (PTR) Checks the IP’s reverse DNS, which Barracuda’s removal process expects to be set properly for a mail server.
• SMTP Diagnostics Verifies your server’s banner and HELO name match its reverse DNS, a basic hygiene check before you ask for removal.

FAQ

How long does Barracuda delisting take?

Barracuda reviews removal requests by hand. Many are processed within a day or so, but it can take longer, and the IP is relisted if spam continues.

Does it cost anything to be removed?

No. Removal from the BRBL through barracudacentral.org is free.