How to get off the Barracuda blocklist
Barracuda keeps a list of email servers that sent email its filters judged to be spam, and businesses that use Barracuda’s spam filter refuse email from them. Look up the server at barracudacentral.org/lookups. If it’s yours, fix the reason, then send one removal request at barracudacentral.org/rbl/removal-request. Barracuda says requests with a valid explanation are usually handled within 12 hours.
Check your own email first. Free, about 90 seconds. You get a grade and a plain-English list of what's working and what isn't.
How you find out
Email to some customers bounces back with a message mentioning Barracuda, barracudacentral.org or “BRBL”. Email to everyone else still arrives, because only businesses using Barracuda’s spam filter check this list. That pattern (one or two customers can’t get your email, everyone else can) is the usual sign.
First, find out whose server it is
Most small businesses send email through Microsoft 365, Google Workspace or another email provider. Their servers send email for thousands of businesses, so when one of them is listed, it usually isn’t about you, and only the provider can get it removed.
- Find the bounce message (the email that came back saying your message wasn’t delivered). It names the list and usually shows the server address that was refused.
- If you send through Microsoft 365, Google Workspace or another provider, forward that bounce to their support. Say which customer it was going to and when. They handle the removal.
- If your email goes out from your own server or your web host, the steps below are yours to follow, or your IT person’s.
Look it up
- Go to barracudacentral.org/lookups and enter the server address from the bounce message (a string of numbers like 203.0.113.25).
- If it says “listed”, that server is on the list. Barracuda only lists server addresses, not web addresses, so you won’t find your business name there.
Why it happens
Barracuda’s list is built by automated systems from the email its filters see.
We can’t tell from the outside why a business was listed, only that it was. The list’s own lookup shows the real reason. Common causes: people marking your email as spam (this often follows cold or bulk email), links to your website appearing in email that got reported, or someone else getting into one of your mailboxes or your website.
Ask for removal
- Fix the reason first. The list is automatic, so a server that keeps sending the same email gets listed again.
- Go to barracudacentral.org/rbl/removal-request.
- Fill in the server address, your email address and your phone number. In the reason box, say in a sentence or two what caused it and what you changed.
- Send it once. Barracuda ignores repeat requests and requests without real information.
- Give it 12 hours, then look the address up again and send a test to the customer whose email bounced.
Stay off it
Send only to people who expect your email, keep newsletters in a newsletter service, and make sure nothing on your website or network sends email you don’t know about.
Want to know the day it happens instead of finding out from a customer? SenderFix Monitor keeps checking the main spam lists for your business and emails you, in plain English, if you show up on one.
What this guide can’t do for you
It covers the common causes. It can’t tell you which of your tools is the one that’s failing, or give you the exact settings for your business and the company that manages your domain. That’s what the Email Fix does. We check every tool that sends email for you and give you steps written for your setup. If we can't find what's wrong with your email settings, you get your $299 back. The guarantee covers your email settings. No settings can fix email sent to people who didn't ask for it, like bought lists or mass emails.
See what's wrong with your email, free
Type in your business's web address (the part after the @ in your email). You'll get a plain-English answer: what's working, what isn't, and what to do next.
Common questions
Why can most people get my email but not one customer?
Barracuda's list is only checked by businesses that use Barracuda's spam filter. If that customer does and your server is listed, their system refuses your email while everyone else still gets it.
How long does Barracuda removal take?
Barracuda says requests with a valid explanation are usually looked at within 12 hours. Send the request once: repeat requests are ignored.
Can I look up my web address on Barracuda?
No. Barracuda's list only holds server addresses. Use the address shown in the bounce message, or ask your email provider which server sent it.
I use Microsoft 365 or Google. What should I do?
Forward the bounce message to their support. The listed server belongs to them, and they're the ones who can request removal.
For your IT person or web developer
You can forward this page as it is. Everything below is written so someone who doesn't work with email settings every day can follow it.
1. Confirm the listed IP
Take the IP from the NDR (or the outbound IP in a sent message's headers) and check it at https://www.barracudacentral.org/lookups. The DNS zone is b.barracudacentral.org. It lists IPs only, built automatically from Barracuda's filter data.
2. Fix the source
If the IP is a shared provider IP (Microsoft 365, Google Workspace, an ESP), open a ticket with the provider. If it's the business's own server or host: check the outbound queue for unexpected volume, look for a compromised mailbox or a web form or script sending mail, make sure reverse DNS (PTR) is set and matches the HELO name, and stop any sends to purchased or old lists.
3. Submit one removal request
At https://www.barracudacentral.org/rbl/removal-request: the IP, a monitored contact email, a phone number, and a short factual reason (cause and what changed). Requests without valid information, and duplicate requests, are ignored. Typical handling is within 12 hours.
4. Check it worked
Look the IP up again, then resend to the recipient that bounced.
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Written by the SenderFix team. Last updated .