Bulk SMTP settings lookup: server, port and encryption for a list of mailboxes
In short: Paste the mailboxes you need to connect to a sending tool and get each one's SMTP and IMAP host, port and encryption, from the provider's own documentation or the domain's published SRV records. Limit: Shows the provider's documented settings; it doesn't test whether a mailbox can log in.
A bulk SMTP settings lookup finds the outgoing and incoming mail server for many addresses at once. Paste up to 100 addresses or domains, or 500 after a free Google sign-in; each domain's MX records name its provider, whose documented SMTP and IMAP host, port and encryption are shown, or the SRV records the domain publishes itself. DNS only, no login. CSV out.
Price: this tool is free. Checking a whole email list is from $9/mo, and the first 100 checks are free with Google, no card. Check your list free nowSee pricing
Sample result
acme.example's MX points to Microsoft 365, so it sends through smtp.office365.com on port 587 with STARTTLS.
- Domain
- acme.example
- SMTP
- smtp.office365.com:587
- IMAP
- outlook.office365.com:993
What this means for you
The settings come from the provider's own help page; the tool never logs in.
- Provider found from MX, or SPF behind a gateway
- RFC 6186 SRV records read
- SMTP and IMAP host, port, encryption
- CSV out
- SMTP
- IMAP
- SRV
By SimpleVerifier Team · Last updated
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Connecting a batch of inboxes to a sending tool?
- Connected inboxes are only as good as the list they send to: bounces count against every one of them. Upload the recipient list at /verify to remove addresses that would bounce.
- The first 100 email checks are free with a Google sign-in, no card. To see how many emails a day each provider allows, use the email sending limits calculator.
How do I find the SMTP settings for many email accounts?
- Paste email addresses or domains, one per line, up to 100 a run or 500 after a free Google sign-in. Each address is reduced to its domain.
- Press Look up settings. Each domain gets an MX and TXT lookup and five SRV lookups, 25 domains a request; no mail server is contacted.
- Read each row: the provider, the SMTP host, port and encryption, the IMAP host and port, and where the settings came from.
- Download the CSV: one row per domain with the SMTP host, port and encryption, the IMAP host and port, and the source.
Example
- You enter
- Three entries:
[email protected],acme.example(MX at Microsoft 365) andglobex.example(an unrecognised mail host). - You get
- gmail.com: smtp.gmail.com:587 STARTTLS, imap.gmail.com:993. acme.example: smtp.office365.com:587 STARTTLS, from the MX records. globex.example: Not found, with its MX host to ask the host about. Download the CSV.
- Limits
- Up to 100 a run without an account and 500 when signed in with Google, counted over a minute. 25 domains a request; DNS only.
How are the settings found?
Free mail domains like gmail.com and outlook.com are matched directly. For any other domain, its MX records name the mailbox provider (Google Workspace, Microsoft 365, Zoho, Yahoo, Fastmail and others), and the row shows the SMTP, IMAP and POP settings from that provider's own help page, the same table as the single SMTP settings lookup. Behind a security gateway such as Proofpoint or Mimecast, the provider named in the domain's SPF record is used, and the row says so.
The tool also reads the SRV records defined by RFC 6186 and RFC 8314: _submissions._tcp, _submission._tcp, _imaps._tcp, _imap._tcp and _pop3s._tcp. A domain that publishes them states its own servers, which the row shows when no known provider matched.
What if the provider isn't recognised?
The row says Not found and shows the MX host. That usually means a web host's or self-hosted mail server; its SMTP host is often mail. plus the domain, on port 465 (SSL/TLS) or 587 (STARTTLS), but only the host's control panel or support can confirm. The tool never guesses a server and presents it as fact.
Does the tool log in or test the servers?
No. It reads DNS only and never opens a connection to a mail server, so it can't tell whether SMTP authentication is turned on for a mailbox. Microsoft 365 lets admins turn SMTP AUTH off per mailbox or for the whole organisation; the Microsoft 365 SMTP AUTH checker explains how to check.
Passwords aren't part of the result. Google and Microsoft accounts need OAuth or an app password, as each provider's row notes.
Who uses this tool, and for what?
- Cold emailers
- Get the SMTP and IMAP settings for a batch of inboxes before connecting them to a sending tool.
- IT teams
- Document the mail servers of every domain a company owns in one CSV.
- Agencies
- Set up client inboxes in a CRM without asking each client for their provider.
- Support teams
- Answer what server do I use for a list of customer domains.
What can’t this tool tell you?
- Shows the provider's documented settings; it doesn't test whether a mailbox can log in.
- Unrecognised and self-hosted servers show Not found unless the domain publishes SRV records.
- Behind a security gateway, the mailbox provider is inferred from SPF, which can be out of date.
- Up to 100 addresses or domains a run without an account, 500 signed in.
Common questions
- How do I find the SMTP server for a list of email addresses?
- Paste them into a bulk SMTP settings lookup like this one. It reads each domain's MX and SRV records and shows the provider's SMTP and IMAP host, port and encryption, with a CSV.
- Is this bulk SMTP settings lookup free?
- Yes. Up to 100 addresses or domains a run without an account, and up to 500 a run when you sign in with Google, with no card.
- What SMTP port should I use?
- 587 with STARTTLS or 465 with SSL/TLS, whichever the provider documents. Port 25 is for server-to-server delivery and is blocked by most networks for sending from apps.
- Does it need my password?
- No. It reads public DNS only and never signs in or connects to a mail server.
- Why does a company domain show Google or Microsoft settings?
- Its MX records point to Google Workspace or Microsoft 365, so its mailboxes use that provider's servers, the same as any other customer of that provider.
- What are SRV records for email?
- DNS records, defined in RFC 6186 and RFC 8314, where a domain publishes its own submission, IMAP and POP servers so mail apps can set themselves up. Few domains publish them.
Sources
A tidy list can still be full of dead addresses.
Extracting, deduplicating and syntax checks all work on the text of an address. None of them can tell whether the mailbox exists. Only the server that hosts it can answer that, through an SMTP check, and that is what the paid product does.
- Upload the cleaned file as it is: CSVs up to 100,000 rows
- A real SMTP mailbox check on every row, with catch-all detection
- Small list? Starter at $9/mo covers 2,500 emails a month, cancel anytime
Plans from $9 a month, cancel anytime, no contract. Sign in with Google and your first 100 email checks are free, no card. The free tools stay free either way.