Enter any domain to look up its MX records. See mail server priorities, identify your email provider, and verify your mail server configuration.
MX (Mail Exchanger) records tell other mail servers where to deliver email for your domain. Each MX record has a priority value — lower numbers are preferred. If the primary server is unavailable, mail is delivered to the next priority server.
MX records are essential for receiving email. Without them, other servers don't know where to deliver mail to your domain. Most email providers (Google Workspace, Microsoft 365, etc.) require you to set specific MX records in your DNS.
When you forward email through different MX configurations, authentication can break. The forwarding server's IP isn't in the original sender's SPF record, and header modifications can invalidate DKIM signatures. Without proper handling, forwarded messages fail DMARC checks at the destination.
ARC-Relay preserves authentication when forwarding through different MX configurations by adding cryptographic ARC seals and using SRS envelope rewriting. Gmail, Outlook, ProtonMail, and Yahoo trust the sealed authentication chain — so your forwarded mail lands in the inbox, not spam.
An MX (Mail Exchanger) record is a DNS record that specifies which mail servers accept email for your domain. Each MX record has a priority number — the lower the number, the higher the preference. When someone sends you an email, their mail server looks up your MX records to find where to deliver it.
Priority (or preference) determines the order mail servers are tried. A server with priority 10 is tried before one with priority 20. If the priority-10 server is down, mail is delivered to the priority-20 server. You can set equal priorities for load balancing across multiple servers.
At minimum, one MX record is required to receive email. Having two or more provides redundancy — if your primary mail server goes down, email is delivered to the backup. Most email providers configure two to five MX records automatically.
This means the sender's server cannot find any MX records for your domain. Check that your MX records are published correctly in your DNS settings. DNS changes can take up to 48 hours to propagate. Also verify that your domain registration hasn't expired.
Yes. When you forward email, the destination uses its own MX records to receive the forwarded message. However, forwarding often breaks SPF authentication because the forwarding server's IP isn't in the original sender's SPF record. ARC-Relay solves this with SRS rewriting and ARC sealing.