Fortinet FortiMail email service provider (ESP)

According to Live Direct Marketing's daily Tranco top-1M scan (September 18, 2026), Fortinet FortiMail is the email service provider (ESP) for 223 domains — 0.04% of 637,944 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.

Key facts

Why Fortinet FortiMail appears in this category

FortiMail Cloud — Fortinet email security gateway.

We classify it as a email security gateway from include: mechanisms in the SPF record matching a maintained provider rule. This is infrastructure attribution from public DNS, not evidence of a direct contract or exclusive use.

Fortinet FortiMail is a commercial email security and filtering appliance operated by Fortinet, a network security company. It is deployed as a gateway solution by organisations to handle inbound and outbound email protection, including antispam, antimalware, attachment filtering, and policy enforcement.

Fortinet's deployment footprint spans smaller and mid-market organisations rather than the largest brands, making it a common element in a diverse receiving infrastructure worldwide. This pattern means senders are likely to encounter FortiMail-protected recipients, but also that each organisation's filtering rules are independently configured — so standardised testing is less effective than direct engagement with customers who report delivery issues.

Where Fortinet FortiMail sits in the Tranco ranking

Tranco rank bandDomainsShare of its base
Top 1,00000.0%
Top 10,00031.3%
Top 100,0002511.2%
Top 1,000,00019386.5%
Unranked20.9%

Top-level domain split

TLDDomainsShare
.com6127.4%
.org177.6%
.de125.4%
.co125.4%
.gr104.5%
.es94.0%
.mx62.7%
.be62.7%
.com.mx52.2%
.gov52.2%

What Fortinet FortiMail users also use

Cross-tabulated from the same daily snapshot — the other email services seen on the same 223 domains.

TypeServiceDomainsShare of Fortinet FortiMail users
MailboxUnknown / Other18984.8%
MailboxMicrosoft 365188.1%
MailboxSelf-Hosted62.7%
MailboxGoogle Workspace31.3%
MailboxBarracuda31.3%
MailboxHornetsecurity20.9%
ESPAmazon SES209.0%
ESPSendGrid (Twilio)188.1%
ESPMailchimp146.3%
ESPMandrill135.8%

Outbound mail relay via SPF authentication

Fortinet FortiMail frequently appears in SPF records as an authorised outbound relay, with organisations adding its IP ranges to permit mail sent through the appliance. This is correct SPF usage for gateway deployments, but it also means the sending domain's reputation becomes partially bound to the FortiMail infrastructure's reputation. Deliverability engineers should ensure DKIM signing is preserved through the relay and that DMARC policy alignment is not disrupted by FortiMail's message processing.

See the full Fortinet FortiMail data page (KPI cards, trend, sample domains) →

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Frequently asked questions

Should I test my email deliverability against Fortinet FortiMail?

Direct testing with individual Fortinet deployments is impractical because each customer's configuration is independent. Monitor real-world delivery to your audience and contact Fortinet-protected organisations directly if delivery issues occur.

How many domains use Fortinet FortiMail?

223 domains in the Tranco top-1M use Fortinet FortiMail as their email service provider (ESP) as of September 18, 2026 (0.04% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.

Is Fortinet FortiMail common enough to affect email deliverability testing?

Fortinet FortiMail accounts for 0.04% 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.

Which countries or TLDs use Fortinet FortiMail most?

Fortinet FortiMail's largest TLD is .com (27.4% of its domains); it appears across 54 TLDs in total.

Other email service provider (ESP)s

Amazon SES (6.20%)SendGrid (Twilio) (4.65%)Mailgun (4.01%)Zendesk (3.76%)Mailchimp (3.58%)Mandrill (3.25%)HubSpot (3.14%)Salesforce (2.55%)Mailjet (Sinch) (2.13%)Cloudflare Email Routing (1.95%)