--- title: "MX Lookup: Check MX Records for Any Domain Free | Prosyo" description: "Free MX lookup: see every mail server for a domain, its priority, IP addresses and email provider (Google Workspace, Microsoft 365 and more). No sign-up." url: "https://prosyo.com/pt/tools/mx-lookup/" image: "https://prosyo.com/wp-content/uploads/2026/10/cropped-Prosyo-Icon-Transparent-1.png" language: "pt" --- Free Tools # MX Record Lookup See which mail servers accept email for any domain, their priority and the provider behind them. MX Record Lookup Instant · free ## What is an MX record lookup? An MX record lookup asks the Domain Name System which mail servers accept email for a domain. MX stands for **mail exchanger**. When anyone sends a message to `name@company.com`, their mail server first looks up the MX records for `company.com`, then delivers the message to the server with the lowest priority number. If that server does not answer, it tries the next one. This free MX lookup shows every MX record for a domain, its priority, the IP addresses behind each mail server and the email provider that runs them, such as Google Workspace, Microsoft 365, Zoho Mail or Proofpoint. It runs in your browser against public DNS-over-HTTPS resolvers, so results are current and nothing you type is stored. ## How to use the MX lookup 1. **Enter a domain** such as `company.com`. You can paste an email address or a full website URL; the tool keeps only the domain. 2. **Press “Look up MX records”.** Results usually arrive in a second or two. 3. **Read the table from the top.** The first row is the primary mail server. Rows with higher numbers are backups. 4. **Check the provider column.** It tells you who hosts email for the domain, which is useful for both troubleshooting and prospecting. ## How to read MX records Every MX record has two parts: a **priority** (also called preference) and a **host name**. A record such as `10 mx1.example.com` means “deliver to mx1.example.com with priority 10”. - **Lower numbers win.** A server with priority 1 is tried before one with priority 10. The actual numbers do not matter, only their order. - **Equal numbers share the load.** Two servers with the same priority receive mail in roughly equal shares. - **The host must be a name, not an IP address.** MX records point to host names, which in turn have A or AAAA records with the IP addresses. The tool resolves those for you. - **The host must not be a CNAME.** Pointing an MX record at an alias breaks the standard and some senders will refuse to deliver. ### What the results tell you | Result | Meaning | What to do | | --- | --- | --- | | One or more MX records | The domain receives email normally. | Nothing, unless the provider is not the one you expect. | | No MX records | Senders fall back to the domain’s A record, which is usually a web server that does not accept mail. | Publish the MX records your email provider gives you. | | Null MX (a single record pointing to “.”) | The domain declares that it accepts no email at all (RFC 7505). | Correct for domains that never receive mail; wrong for any domain you send from. | | Domain does not exist | The DNS returned NXDOMAIN. | Check the spelling. An email address at this domain will always bounce. | ## MX records for the most common providers These are the patterns the tool recognises. If you are setting up a domain, copy the exact values from your provider’s admin console. | Provider | Typical MX host | | --- | --- | | Google Workspace | `smtp.google.com` (priority 1) on newer accounts, or `aspmx.l.google.com` plus `alt1` to `alt4` on older ones | | Microsoft 365 | `yourdomain-com.mail.protection.outlook.com` (priority 0) | | Zoho Mail | `mx.zoho.com`, `mx2.zoho.com`, `mx3.zoho.com` (or the .eu, .in and .com.au regions) | | Proton Mail | `mail.protonmail.ch` and `mailsec.protonmail.ch` | | Fastmail | `in1-smtp.messagingengine.com` and `in2-smtp.messagingengine.com` | | Proofpoint, Mimecast, Barracuda | Hosts ending in `pphosted.com`, `mimecast.com` or `barracudanetworks.com`: an email security gateway in front of the real mailbox provider | ## Why MX records matter for cold email ### For the domain you send from Every domain you send cold email from should be able to receive email. Replies have to land somewhere you will read them, bounce notifications need a home, and mailbox providers treat a domain that cannot receive as a weak, possibly throwaway sender. New secondary domains bought for outreach are the most common culprits: the mailboxes exist in Google Workspace or Microsoft 365, but nobody published the MX records. Run this lookup, then the full [Domain Health Checker](https://prosyo.com/tools/domain-health-checker/), before warm-up starts. ### For the people you write to MX records also tell you useful things about a prospect’s company before you send: - **Whether the domain can receive at all.** If a domain has no MX records, every address there bounces, and bounces damage your sender reputation. The [Email Verifier](https://prosyo.com/tools/email-verifier/) runs this check across a whole list. - **Which provider they use.** Google Workspace and Microsoft 365 filter differently, so teams often look at their reply and bounce rates by recipient provider. - **Whether a security gateway sits in front.** Proofpoint, Mimecast and Barracuda are stricter than standard filtering and more common at larger companies. Plain, short, link-light emails fare best against them. - **A hint about company size and stack.** An enterprise gateway suggests an IT team; a basic host-provided mail server suggests a small business. ## Common MX problems and how to fix them ### Mail is not arriving after switching provider Old MX records left in place alongside the new ones split your mail between two systems. Remove every MX record from the old provider once the new one is set up, and check the result here. Remember that DNS changes take time to reach all senders, up to the record’s TTL, which is often an hour. ### Priorities are in the wrong order If a backup server has a lower number than the primary, most mail goes to the backup. Make the primary server’s number the lowest. ### The MX host has no IP address If the IP column shows a dash, the mail server name does not resolve. Usually it is a typo or a server that was decommissioned. Senders will try the next MX and may eventually bounce the message. ### MX points to the website host Some web hosts publish MX records for their own mail service by default. If you use Google Workspace or Microsoft 365, those defaults must be replaced, or mail will go to an inbox nobody checks. ## MX records, SPF, DKIM and DMARC: how they fit together MX records control **incoming** mail. The other three control how receivers judge your **outgoing** mail: - **SPF** lists the servers allowed to send for your domain. Check it with the [SPF Checker](https://prosyo.com/tools/spf-checker/). - **DKIM** signs each message so receivers can confirm it came from you unaltered. Check it with the [DKIM Checker](https://prosyo.com/tools/dkim-checker/). - **DMARC** tells receivers what to do when SPF and DKIM fail. Check it with the [DMARC Checker](https://prosyo.com/tools/dmarc-checker/). A common mistake is assuming that because MX points to Google, outgoing mail is authenticated too. It is not; SPF and DKIM must be published separately. ## MX lookup from the command line If you prefer a terminal, these commands return the same records: - macOS and Linux: `dig MX company.com +short` - Windows: `nslookup -type=mx company.com` The difference is that this tool also resolves each mail server’s IP address and names the provider, and runs from any browser without installing anything. ## How to add or change MX records, step by step The exact screens differ by DNS host, but the steps are the same everywhere. Your DNS host is wherever your domain’s nameservers point: often your registrar (GoDaddy, Namecheap, Squarespace Domains), or a service such as Cloudflare. The [DNS Lookup](https://prosyo.com/tools/dns-lookup/) shows your NS records if you are not sure. 1. **Get the values from your email provider.** Google Workspace, Microsoft 365, Zoho and the others all show the exact MX hosts and priorities during setup. 2. **Open the DNS settings** for the domain at your DNS host. 3. **Delete any MX records you are replacing**, including defaults your web host added for its own mail service. 4. **Add each new MX record.** Type: MX. Host or name: `@` (meaning the domain itself). Value: the mail server host name. Priority: the number your provider gives. TTL: leave the default or use one hour. 5. **Save, wait a few minutes and run this lookup.** If the old records still appear, your DNS host has not published the change yet, or you edited records at a host your nameservers do not use. 6. **Send a test email** to the domain from an outside account and confirm it arrives. On Cloudflare, MX records cannot be “proxied”; they are always DNS-only, which is correct. On some hosts the host field must be left empty instead of `@`. If a provider asks you to verify the domain with a TXT record first, add that before the MX records. ## MX, A, AAAA and CNAME: what is the difference? | Record | What it does | Relation to email | | --- | --- | --- | | MX | Names the servers that receive mail for the domain. | The record senders look up first. | | A / AAAA | Map a host name to an IPv4 / IPv6 address. | Each MX host needs one; the domain’s own A record is the fallback when there is no MX. | | CNAME | Makes one name an alias of another. | An MX record must never point at a CNAME. DKIM records, by contrast, are often CNAMEs. | | TXT | Holds text, including SPF, DKIM and DMARC. | Controls how your outgoing mail is authenticated. | ## Troubleshooting: “my email is not arriving” Work through this list in order; most incoming-mail problems are found in the first three steps. 1. **Run this MX lookup.** Are the records there, and do they point to the provider you actually use? 2. **Check for leftovers.** Records from an old provider or a web host’s default mail service split or hijack delivery. 3. **Check the nameservers.** If you edited DNS at your registrar but the domain uses Cloudflare’s nameservers (or the reverse), your changes are not live. 4. **Check each MX host resolves to an IP address.** A dash in the IP column means the name is wrong or the server is gone. 5. **Check the mailbox exists** at the provider and has no forwarding rule sending mail elsewhere. 6. **Ask the sender for the bounce message.** It usually states the exact reason, such as “mailbox not found” or “no MX record”. 7. **Look at quarantine** in your provider’s admin console, especially if a security gateway sits in front. ## Email security gateways, briefly When a domain’s MX records point to Proofpoint, Mimecast, Barracuda or a similar service, every incoming message passes through that filter before it reaches the company’s actual mailboxes in Google Workspace or Microsoft 365. Gateways are stricter than standard filtering: they rewrite links, scan attachments, hold messages from new senders and score bulk-looking mail harshly. For outbound teams, that means first emails to these companies should be short, plain-text and link-free, sent from an authenticated, warmed-up mailbox at a modest daily volume. It does not mean avoiding them; many of the best-fit accounts for B2B products use a gateway. ## Bounces, MX records and your sender reputation When you email an address at a domain with broken or missing MX records, the message bounces. A few bounces are normal; a high bounce rate tells mailbox providers your list is old or scraped, and they lower your sender reputation for everyone you write to afterwards. A common working target for cold email is a bounce rate under 2%. The cheapest way to stay there is to check every new list before it enters a sequence: remove addresses at domains that do not exist or cannot receive, and remove disposable and role-based addresses. The [Email Verifier](https://prosyo.com/tools/email-verifier/) does all of this for up to 50 addresses at a time. ## Glossary - **MX record**: a DNS record naming a mail server for a domain, with a priority. - **Priority (preference)**: the order servers are tried in; lowest first. - **TTL**: how long other servers may cache a record before checking again. - **Null MX**: a single MX of “.” that declares the domain accepts no email. - **NXDOMAIN**: the DNS answer meaning the domain does not exist. - **Security gateway**: a filtering service that receives mail before the real mailbox provider. - **Nameservers**: the servers that hold a domain’s DNS records; where you edit them. ## Using MX data in prospecting When you build a target list, the email provider is a light but useful signal. A list split by provider lets you see whether replies drop for one provider, which usually points to a filtering or reputation issue rather than a messaging one. It also helps you decide what to send first: short, plain-text first touches perform more consistently across strict gateways than long, link-heavy ones. Pair this with the [Cold Email Grader](https://prosyo.com/tools/cold-email-grader/) to keep first emails short and specific. ## How Prosyo helps Prosyo verifies contact details before it sends, so addresses at domains that cannot receive email never reach your sequence, and it sends from your own mailboxes inside safe daily limits. It then writes personal LinkedIn and email outreach from what each prospect actually posted and drafts every reply. [Try it free for 7 days](https://prosyo.com/pricing/), no card required. ## Related free tools These tools are often used together with the MX Lookup. All of them are free, and the checkers and calculators run instantly in your browser. - [Domain Health Checker](https://prosyo.com/tools/domain-health-checker/): Score your sending domain on MX, SPF, DKIM, DMARC, BIMI, MTA-STS and blocklists in one click, with a fix for everything that fails. - [DNS Lookup](https://prosyo.com/tools/dns-lookup/): Query A, AAAA, CNAME, MX, TXT, NS, SOA and CAA records for any name from a public resolver. - [Email Verifier](https://prosyo.com/tools/email-verifier/): Check up to 50 addresses for syntax, mail servers, disposable and role-based addresses and typos, then export a CSV. - [SPF Checker](https://prosyo.com/tools/spf-checker/): Validate your SPF record, count its DNS lookups against the limit of 10 and see every include it depends on. ## Frequently asked questions ### How do I find the MX records for a domain? Enter the domain in the MX lookup above. It lists every MX record with its priority, the mail server’s IP addresses and the provider that runs it. From a terminal you can also run dig MX domain.com or nslookup -type=mx domain.com. ### What does the MX priority number mean? Lower numbers are tried first. A record with priority 1 receives mail before one with priority 10, which acts as a backup. Records with the same number share the load. ### Can a domain have no MX records? Yes. Without MX records, senders fall back to the domain’s A record, which is usually a web server that does not accept email, so mail typically bounces. Any domain that should receive email needs MX records. ### What is a null MX record? A single MX record that points to a dot with priority 0. It tells senders that the domain accepts no email at all, so they bounce messages immediately instead of retrying. ### How long do MX record changes take to work? Usually minutes, but other servers may keep using the old records until their cached copy expires, up to the record’s TTL. Many providers use one hour; some use a day. ### Do MX records affect whether my emails go to spam? Indirectly. MX records control incoming mail, but a domain that cannot receive email looks less trustworthy to mailbox providers, and replies to your outreach will be lost. Outgoing placement depends mostly on SPF, DKIM, DMARC and your sending reputation. ### Why does my domain show a different provider than I expected? Either old MX records are still published, your web host added its own mail service by default, or a security gateway such as Proofpoint or Mimecast sits in front of your real provider. Remove records you no longer use and keep only your provider’s. ### Can I use MX records to find out what email provider a company uses? Yes. The provider column shows who hosts email for the domain, for example Google Workspace or Microsoft 365, and whether a security gateway filters incoming mail. This information is public DNS data. ### Is this MX lookup tool free? Yes, with no sign-up and no limits for normal use. It runs in your browser and queries public DNS-over-HTTPS resolvers. ## Ready to Accelerate Your Growth? Launch smarter campaigns, convert more leads, and scale your business with ease — all in one place. [Get Started Now](https://prosyo.com/pt/) [Book a Demo](https://prosyo.com/pt/pricing/)