How to Find the SMTP Settings for Any Email Address (Host, Port, Encryption)

Your SMTP settings come from whoever hosts your mailbox, and the domain's MX records tell you who that is. Enter your address or domain in the SMTP settings lookup: it reads the MX records, names the provider and shows the outgoing host, port and encryption from that provider's own documentation.

Find SMTP settings for an address →

Find them with the lookup

1. Open the SMTP settings lookup.
2. Type the address or domain, such as [email protected], and press Find SMTP settings. Or pick a provider from the list.
3. Copy the host, port and encryption into your app, printer or sending tool.
4. If sign-in fails, open the linked provider page: authentication rules change more often than hosts and ports.

Find them by hand

Step one is the MX record:

dig +short mx simpleverifier.com
# 1 smtp.google.com.

smtp.google.com is the MX value Google gives for Google Workspace, so this domain's mail is on Google and the sending settings are Google's. A *.mail.protection.outlook.com host means Microsoft 365.

Step two is checking the server answers on the port you plan to use. We ran these on 8 November 2026:

printf "EHLO example.com\nQUIT\n" | openssl s_client -starttls smtp -connect smtp.gmail.com:587 -crlf -quiet 2>/dev/null | grep AUTH
# 250-AUTH LOGIN PLAIN XOAUTH2 PLAIN-CLIENTTOKEN OAUTHBEARER XOAUTH

printf "EHLO example.com\nQUIT\n" | openssl s_client -starttls smtp -connect smtp.office365.com:587 -crlf -quiet 2>/dev/null | grep AUTH
# 250-AUTH LOGIN XOAUTH2

Both upgraded to TLS 1.3 and listed the sign-in methods they accept. That proves the host and port, not your account.

The settings for the two biggest providers

• Gmail and Google Workspace: smtp.gmail.com, port 465 with implicit SSL/TLS or 587 with STARTTLS, per Google's IMAP, POP and SMTP page.
• Microsoft 365: smtp.office365.com, port 587 (recommended) or 25, STARTTLS with TLS 1.2 or 1.3, signed in as the sending mailbox, per Microsoft's guide to sending from a device or application. The same page says a device that defaults to 465 doesn't support the TLS versions Microsoft 365 needs, and that SMTP AUTH is off for organizations created after January 2020 unless enabled per mailbox.

Port 25 is for server-to-server mail and is often blocked outbound; see why cloud providers block port 25.

Next step: check who you're about to email

Once your app can send, the next thing that hurts it is bouncing off dead addresses. Upload your list at /verify to check every mailbox without sending. The first 100 checks are free with a Google sign-in, no card.

Pro, $39 a month: Unlimited email verification.* Never metered, never cut off. See pricing.

*Fair use: the first 100,000 checks a month at full speed, then slower, never cut off.

More: Microsoft 365 SMTP AUTH and cold email, check a new domain is ready to send email.