--- title: "Bulk MX Lookup | Free Cold Email Tool | Warminboxes" description: "Look up the mail provider behind a whole list of domains at once, with the split and a CSV to segment from." url: https://warminboxes.com/bulk-mx-lookup breadcrumb: "Home > Free Tools > Bulk MX Lookup" --- # Bulk MX Lookup Look up the mail provider behind a whole list of domains at once, with the split and a CSV to segment from. Free to use, no account required. Part of the WarmInboxes free deliverability toolkit. [All free deliverability tools →](https://warminboxes.com/deliverability-tools) ## Other free deliverability tools The rest of the toolkit, all free and all without an account. - [Blacklist Checker](https://warminboxes.com/blacklist-checker) — Check if your domain or IP is listed on 20+ major email blacklists in seconds. - [Domain Reputation Checker](https://warminboxes.com/domain-reputation-checker) — Work out whether your domain is actually the problem — what’s listed, what’s broken, and what it rules out. - [Deliverability Checker](https://warminboxes.com/deliverability-checker) — Grade your domain A to F across SPF, DKIM, DMARC, MX, blacklists and domain age. - [DMARC Report Analyzer](https://warminboxes.com/dmarc-report-analyzer) — Read the daily DMARC XML your domain receives: who sends as you, what passed, what only failed alignment. - [DMARC Checker](https://warminboxes.com/dmarc-checker) — Validate and analyse your DMARC record, policy, tags and verdicts explained. - [SPF Checker & Generator](https://warminboxes.com/spf-checker) — Look up existing SPF records or build a new one, with recursive lookup counting. - [DKIM Checker](https://warminboxes.com/dkim-checker) — Auto-scan 26 common selectors and validate your DKIM signing key strength. - [MX Lookup](https://warminboxes.com/mx-lookup) — Look up a domain’s MX records with priority, address and TTL, and identify the mail provider behind them. - [Email Provider Checker](https://warminboxes.com/email-provider-checker) — Find out who hosts a domain’s email — Google, Microsoft, Zoho, or a security gateway — from one lookup. - [SPF Lookup Counter](https://warminboxes.com/spf-lookup-counter) — Count the DNS lookups your SPF record costs, see the include tree, and find out how close you are to the limit. - [DKIM Selector Finder](https://warminboxes.com/dkim-selector-finder) — Find which DKIM selectors a domain publishes without knowing the selector first. Scans 26 common ones. - [Email Authentication Checker](https://warminboxes.com/email-authentication-checker) — SPF, DKIM, DMARC, MX, BIMI and MTA-STS for one domain in one pass, with the optional ones marked optional. - [DMARC Alignment Checker](https://warminboxes.com/dmarc-alignment-checker) — Paste a real message’s headers and find out why DMARC failed when SPF or DKIM passed. - [One-Click Unsubscribe Checker](https://warminboxes.com/one-click-unsubscribe-checker) — Check whether a message’s List-Unsubscribe headers meet the one-click requirement Google and Yahoo enforce. - [Reverse DNS Lookup](https://warminboxes.com/reverse-dns-lookup) — Look up the PTR record for an IP and check whether it forward-confirms, which is the pair receivers test. - [IP Reputation Checker](https://warminboxes.com/ip-reputation-checker) — Blocklist listings and reverse DNS for a sending IP, reported as findings rather than an invented score. - [Tracking Domain Checker](https://warminboxes.com/tracking-domain-checker) — Check the domain your tracked links point at: DNS, certificate, URL blocklists, and whether it is yours or your platform’s. - [Gmail Clipping Checker](https://warminboxes.com/gmail-clipping-checker) — Find out whether Gmail will clip your email at 102KB, and exactly what is taking up the room. - [Email Link & Pixel Scanner](https://warminboxes.com/email-link-scanner) — Pull every link, image host and tracking pixel out of an email and check each domain against URL blocklists. - [Bulk Sender Requirements Checker](https://warminboxes.com/bulk-sender-requirements-checker) — Check the Gmail, Yahoo and Microsoft bulk sender requirements — and see which ones no external tool can verify. - [DNS Checker](https://warminboxes.com/dns-checker) — Query MX, TXT, CNAME, A and all other DNS record types for any domain. - [TXT Record Lookup](https://warminboxes.com/txt-record-lookup) — Every TXT record on a domain, each one identified — plus the mistakes that quietly break authentication. - [A Record Lookup](https://warminboxes.com/a-record-lookup) — The IPv4 addresses a hostname resolves to, with TTLs, the CNAME chain, and whether they are public at all. - [AAAA Record Lookup](https://warminboxes.com/aaaa-record-lookup) — The IPv6 addresses a hostname resolves to, and why an unwanted AAAA record on a mail host costs you delivery. - [SOA Record Lookup](https://warminboxes.com/soa-lookup) — The zone’s SOA record, read for the field that decides how long a new DNS record keeps reading as missing. - [Domain Expiry Checker](https://warminboxes.com/domain-expiry-checker) — Monitor domain expiration dates and catch renewals before they lapse. - [Record Generator](https://warminboxes.com/record-generator) — Build correct SPF, DKIM and DMARC records with presets for every major ESP. - [ESP Segmentation & Mailbox Calculator](https://warminboxes.com/esp-segmenter) — Split your list by Google, Microsoft and gateway inboxes, then get told how many mailboxes to buy. - [Cold Email Infrastructure Calculator by Recipient ESP](https://warminboxes.com/esp-calculator) — Upload your list and get the exact Google, Microsoft and Azure inboxes to buy for the people on it. - [Nameserver Checker](https://warminboxes.com/nameserver-checker) — One domain or a whole CSV: get NS records and the DNS provider behind every domain. - [SURBL Checker](https://warminboxes.com/surbl-checker) — Bulk-check domains against the SURBL URI blacklist. - [Spamhaus DBL Checker](https://warminboxes.com/spamhaus-checker) — Bulk Spamhaus Domain Block List lookups for your sending and link domains. Coming soon. - [Google Domain Checker](https://warminboxes.com/google-domain-checker) — See if a domain is already tied to a Google Workspace account or clear for fresh inboxes. - [Email Verifier](https://warminboxes.com/email-verifier) — SMTP-level mailbox verification with catch-all detection. - [Spam Checker](https://warminboxes.com/spam-checker) — Scan your subject and body for 200+ weighted spam triggers and formatting red flags. - [CSV List Cleaner](https://warminboxes.com/csv-cleaner) — Dedupe and scrub lead lists entirely in your browser, nothing gets uploaded. - [Spintax & Liquid Tester](https://warminboxes.com/spintax-tester) — Preview every spintax variation and personalization variable before sending. - [Domain & Inbox Planner](https://warminboxes.com/inbox-planner) — Target volume in, exact domains and inboxes needed out, with a safe ramp-up plan. - [Inbox Rotation Planner](https://warminboxes.com/inbox-rotation-planner) — Split your fleet into rotating batches with a schedule, no burned inboxes. - [Pre-Send Checker](https://warminboxes.com/pre-send-checker) — Catch broken merge tags, dupes and spintax errors, and forecast send volume. - [Suppression Checker](https://warminboxes.com/suppression-checker) — Check any list against customers, unsubscribes and previously contacted companies. - [Bounce Analyzer](https://warminboxes.com/bounce-analyzer) — Paste bounce messages, get the root cause in plain English plus a pause-or-continue verdict. - [Outlook SCL Analyzer](https://warminboxes.com/scl-analyzer) — Paste Outlook headers and find out exactly why the message went to Junk. - [Waterfall Calculator](https://warminboxes.com/waterfall-calculator) — Find the cheapest verifier order and your true cost per usable email. - [Sequencer CSV Converter](https://warminboxes.com/sequencer-csv-converter) — Convert lead CSVs between Instantly, Smartlead and Email Bison formats. - [CSV Combiner](https://warminboxes.com/csv-combiner) — Merge multiple lead lists into one, matching headers and deduping emails. - [Unsubscribe Generator](https://warminboxes.com/unsubscribe-generator) — CAN-SPAM and GDPR compliant opt-out footers in plain text and HTML. - [Inbox Previewer](https://warminboxes.com/inbox-previewer) — See your sender, subject and snippet exactly as Gmail and Outlook render them. - [Header Analyzer](https://warminboxes.com/header-analyzer) — Paste raw headers: SPF, DKIM, DMARC, alignment and hops explained in plain English. - [BIMI Checker](https://warminboxes.com/bimi-checker) — Validate your brand logo record, SVG, VMC and the DMARC enforcement Gmail requires. - [CNAME Checker](https://warminboxes.com/cname-checker) — Follow the full CNAME chain and catch the mistakes that break a cold email tracking domain. - [SSL Certificate Checker & Generator](https://warminboxes.com/ssl-checker) — Read any host’s TLS certificate — issuer, expiry, names and chain — or build the config for a new one. - [MTA-STS Checker](https://warminboxes.com/mta-sts-checker) — Validate your _mta-sts record and policy file: enforce mode, MX patterns and TLS-RPT.