Glossary

Accept-all — see Catch-all.

Blacklist / blocklist — a public list of senders (IP addresses or domains) that many mail servers refuse or filter. Spamhaus is the best known.

Bounce — an email that comes back undelivered. A hard bounce means the address doesn’t exist; a soft bounce is temporary, like a full inbox.

Catch-all — a domain that accepts mail for every address, real or not, so a single mailbox can’t be confirmed. More →

Credit — what you spend in EmailShield. One credit checks one address. More →

DKIM — a signature on outgoing email that proves it came from your domain and wasn’t changed on the way.

DMARC — a DNS record that tells receivers what to do with mail that fails SPF and DKIM.

Disposable address — a temporary inbox from a throwaway email service.

Greylisting — a mail server deliberately answering “try again later” to unfamiliar senders.

ICP — ideal customer profile: a short description of the companies and people you sell to.

MX record — the DNS record that says which mail server receives email for a domain. No MX record, no mail.

Role address — a shared inbox such as info@, sales@ or support@ rather than a person.

Sender reputation — how much mailbox providers like Google and Microsoft trust your domain and inboxes. Bounces and spam complaints lower it.

Sequencer — the tool that sends your cold emails and follow-ups on a schedule (Instantly, PlusVibe, Smartlead…).

SPF — a DNS record listing the servers allowed to send email for your domain.

Spam trap — an address that exists only to catch senders who don’t clean their lists. Mailing one can get you blacklisted.

Verification — checking that an email address exists and accepts mail, without sending an email to it.

Warm-up — gradually increasing how much a new inbox sends so mailbox providers learn to trust it.