ns.checkeremail.com

ns.checkeremail.com is a mail server (MX) used by 1 checked domain. Based on public DNS, it looks healthy.

IP & reverse DNS

IP address	Reverse DNS (PTR)	FCrDNS	DNSBL
52.101.42.84	mail-co1pr02cu00204.inbound.protection.outlook.com	Yes	Not listed
52.101.41.198	mail-byapr05cu00706.inbound.protection.outlook.com	Yes	Not listed
52.101.60.2	mail-bnypr05cu00102.inbound.protection.outlook.com	Yes	Not listed
52.101.194.167	mail-ch0pr02cu00107.inbound.protection.outlook.com	Yes	Not listed

FCrDNS (forward-confirmed reverse DNS) passes when the IP’s PTR name resolves back to the same IP. It is a key signal that a mail server is legitimately configured; servers without it are widely treated as suspicious.

Server software

Detected software	Microsoft Exchange / 365 (from SMTP banner)
SMTP banner	`220 CY4PEPF000392DA.mail.protection.outlook.com Microsoft ESMTP MAIL Service ready at Tue, 3 Nov 2026 22:30:08 +0000 [08DF36D71149F180]`

Captured passively during an earlier check — we do not actively scan mail servers.

Domains using this mail server

grainger.com

What does this mean?

These are public DNS facts about the mail server ns.checkeremail.com — the host that other servers connect to when delivering email for the domains above. We do not actively probe it over SMTP; the checks here are reverse DNS, forward-confirmed rDNS and public blocklists.

To look up a specific domain’s mail setup use the MX Lookup, or verify an address with the email checker. Learn more in email servers explained.