According to Live Direct Marketing's daily Tranco top-1M scan (July 13, 2026), Barracuda Email Security is the email service provider (ESP) for 343 domains — 0.06% of 617,702 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
Barracuda Email Security is a cloud-based email filtering and protection service operated by Barracuda Networks, a security software company. It sits in the email infrastructure ecosystem as a gateway solution for organizations seeking to defend against phishing, spam, malware, and data loss — typically deployed by businesses of all sizes, but particularly common among mid-market and smaller organizations.
When you encounter Barracuda Email Security's SPF include mechanisms across the web, you are looking at a distributed presence across smaller and mid-market sites rather than the largest enterprise brands, spread globally across many top-level domains with .com leading. For senders and receivers, this means you are likely to encounter Barracuda's infrastructure when emailing smaller organizations or those without in-house email ops teams — it is a common choice for firms that outsource their security posture rather than build it in-house.
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 0 | 0.0% |
| Top 100,000 | 25 | 7.3% |
| Top 1,000,000 | 276 | 80.5% |
| Unranked | 42 | 12.2% |
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 117 | 34.1% | |
| .co.uk | 102 | 29.7% | |
| .org.uk | 27 | 7.9% | |
| .org | 22 | 6.4% | |
| .ac.uk | 13 | 3.8% | |
| .gov.uk | 10 | 2.9% | |
| .net | 8 | 2.3% | |
| .ie | 7 | 2.0% | |
| .de | 3 | 0.9% | |
| .be | 3 | 0.9% |
Cross-tabulated from the same daily snapshot — the other email services seen on the same 343 domains.
| Type | Service | Domains | Share of Barracuda Email Security users |
|---|---|---|---|
| Mailbox | Barracuda | 288 | 84.0% |
| Mailbox | Microsoft 365 | 32 | 9.3% |
| Mailbox | EmailSecurity.app gateway | 6 | 1.7% |
| Mailbox | Mimecast | 6 | 1.7% |
| Mailbox | Unknown / Other | 4 | 1.2% |
| Mailbox | Google Workspace | 3 | 0.9% |
| ESP | Mailchimp | 48 | 14.0% |
| ESP | Amazon SES | 47 | 13.7% |
| ESP | SendGrid (Twilio) | 41 | 12.0% |
| ESP | Mandrill | 40 | 11.7% |
Barracuda Email Security operates as an incoming mail gateway for its customers, sitting between the public internet and the target organization's mailbox. For senders, this means SPF and DKIM validation happen at Barracuda's infrastructure before mail reaches the customer's own authentication systems. Your mail's reputation with Barracuda's filtering rules, not just your domain reputation, affects delivery to Barracuda-protected inboxes, and failures at the gateway level can reject mail before the recipient's server ever sees it.
See the full Barracuda Email Security data page (KPI cards, trend, sample domains) →
Barracuda Email Security is a cloud-based email gateway that filters inbound mail for organizations. If your recipients use Barracuda, your mail must pass its filtering rules to reach their inbox — maintaining good sender reputation, avoiding spam triggers, and ensuring DKIM/SPF alignment will help your mail pass through.
343 domains in the Tranco top-1M use Barracuda Email Security as their email service provider (ESP) as of July 13, 2026 (0.06% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.
Barracuda Email Security accounts for 0.06% of SPF-publishing domains in the top 1M. Whether you should seed a test mailbox there depends on how much of your audience it represents — the co-usage table above shows the services it appears alongside most.
Barracuda Email Security's largest TLD is .com (34.1% of its domains); it appears across 36 TLDs in total.