Mimecast receives mail for 146 of 9,971 popular domains we measured in November 2026. Below: the records it needs and how its customers actually set them.
MX hosts depend on the account's region, for example us-smtp-inbound-1.mimecast.com and us-smtp-inbound-2.mimecast.com, or eu-smtp-inbound-1/2.mimecast.com.
Add include:_netblocks.mimecast.com to the domain's single SPF record, for example:
v=spf1 include:_netblocks.mimecast.com -all9 of 146 Mimecast customers in our sample (6.2%) have this include in their SPF record.
TXT record at <selector>._domainkey.<domain>; the selector is chosen when the DKIM key is created in the Mimecast administration console.
Publish a TXT record at _dmarc.<domain> once SPF and DKIM pass for all mail you send, start with p=none and a reporting address, then move to p=quarantine or p=reject:
v=DMARC1; p=reject; rua=mailto:dmarc-reports@<domain>Provider site: https://www.mimecast.com/
146 customer domains in the sample (accent bars) compared with all 9,971 measured domains (grey bars).
The highest-ranked domains in the sample whose MX records point to Mimecast.
Check one yourself:
Customer-specific parts replaced by <domain> and digits by <n>.
| MX host pattern | Domains |
|---|---|
us-smtp-inbound-<n>.mimecast.com | 60 |
eu-smtp-inbound-<n>.mimecast.com | 27 |
usb-smtp-inbound-<n>.mimecast.com | 22 |
de-smtp-inbound-<n>.mimecast.com | 21 |
au-smtp-inbound-<n>.mimecast.com | 8 |
ca-smtp-inbound-<n>.mimecast.com | 3 |
service-alpha-inbound-a.mimecast.com | 3 |
service-alpha-inbound-b.mimecast.com | 3 |
Source: our own scan of November 2026 (2026-11-11), 9,971 of the top 10,000 domains of the Tranco list Y895G that answered in DNS. Method and data.