The glossary

33 terms from business email and DNS, explained in plain words, with where they matter in iResendly.

A

Alias: An extra address that delivers into an existing mailbox, such as hello@ arriving in Sara's inbox. In iResendly, aliases are free and don't use a mailbox seat.Aliases and forwarding
Auto-reply(Out-of-office, vacation reply): An automatic answer sent to people who email you, often while you're away. Good auto-replies answer each sender only once in a while and skip mailing lists and no-reply senders.Auto-replies and signatures

Blocked sender: A sender or whole domain you've chosen not to receive mail from. In iResendly webmail, mail from a blocked sender isn't delivered at all, not even to Spam.Spam, viruses and blocked senders
Bounce message(Non-delivery report, NDR): An automatic email telling you a message you sent couldn't be delivered, usually with a reason such as an unknown address or a full mailbox.

Catch-all: A setting that decides what happens to mail sent to addresses at your domain that don't exist: deliver it to one mailbox or drop it. Catch-alls attract a lot of spam.Catch-all

DKIM(DomainKeys Identified Mail): A digital signature on outgoing mail, checked against a public key in your domain's DNS, that proves a message came from your domain unchanged. In iResendly it's set up when you verify the domain.Mail DNS: MX, SPF and DMARC
DMARC: A DNS record that tells receiving servers what to do with mail claiming to be from your domain that fails SPF and DKIM, and where to send reports. It's published as a TXT record at _dmarc.Mail DNS: MX, SPF and DMARC
DMARC policy: The p= part of a DMARC record: none only monitors, quarantine asks receivers to treat failing mail as spam, and reject asks them to refuse it. iResendly sends incoming mail that fails its sender's p=reject policy to Spam.Spam, viruses and blocked senders
DNS propagation: The time it takes for a DNS change to be seen everywhere, as servers around the internet refresh their cached copies. It's usually minutes but can take up to 48 hours, depending on the record's TTL.Add and verify a domain
DNS record: An entry in your domain's DNS settings that tells the internet something about the domain, such as where its website is or where its mail goes. Common types for email are MX and TXT.Mail DNS: MX, SPF and DMARC
Domain verification: Proving you control a domain by publishing records that a service gives you at your DNS provider. In iResendly, a domain must be verified before mail can be turned on for it.Add and verify a domain

Forwarding: Automatically sending new mail on to another address, with or without keeping a copy in the original mailbox.Aliases and forwarding

IMAP(Internet Message Access Protocol): A standard way for mail apps to read mail stored on a server. Folders and read status stay on the server, so every device sees the same mailbox.

Mailbox: An email account for one address, with its own password, storage and folders. In iResendly, each mailbox uses one seat on your plan.Create and manage mailboxes
MX record(Mail exchanger): The DNS record that tells other servers where to deliver email for your domain. All of a domain's MX records should point to the same mail service, or some mail will go astray.Mail DNS: MX, SPF and DMARC

Nameserver: The server that holds your domain's DNS records and answers questions about them. Your nameservers decide where you edit DNS, which may be your registrar or another DNS provider.

Phishing: Email made to look like it's from someone you trust, to trick you into clicking a link, opening an attachment or giving away passwords or payment details. Check the real sender address and don't sign in through links in unexpected emails.
Plus addressing(Subaddressing): Adding a + and a word to your address, such as sara+news@, so mail still reaches you but can be sorted or traced. It works automatically for iResendly mailboxes.Aliases and forwarding
POP3(Post Office Protocol): An older standard for downloading mail from a server to one device, often removing it from the server. Unlike IMAP, it doesn't keep folders in sync across devices.
Postmaster address: The postmaster@ address that email standards expect every mail domain to accept, along with abuse@, for reports about mail problems. In iResendly, mail to both goes to the domain's first mailbox.Catch-all
PTR record(Reverse DNS): A DNS record that maps an IP address back to a host name. Receiving servers check that a sending server's PTR record looks right, and are suspicious of mail from servers without one.

Safe sender: A sender or domain you trust, whose mail should always reach your inbox rather than spam.Spam, viruses and blocked senders
Shared mailbox: A mailbox that several people can open, such as a team's support inbox. An alias is a simpler way to have a shared address deliver to one person's mailbox.
Signature: The block of text added to the end of the emails you write, usually with your name, role and contact details.Auto-replies and signatures
SMTP(Simple Mail Transfer Protocol): The standard that mail servers use to send email to each other, and that mail apps use to hand outgoing mail to a server.
Spam folder(Junk): The folder where mail judged to be unwanted is put instead of the inbox. Marking mail as spam or not spam helps the filter learn what you want.Spam, viruses and blocked senders
SPF(Sender Policy Framework): A TXT record listing the servers allowed to send mail for your domain. A domain should have only one SPF record; to allow another service, add it to the existing record.Mail DNS: MX, SPF and DMARC
Spoofing: Forging the From address so an email looks like it came from someone else. SPF, DKIM and DMARC let receiving servers spot mail that falsely uses your domain.
Storage quota(Mailbox size): The amount of mail, including attachments, a mailbox can hold. In iResendly, a full mailbox keeps receiving mail but can't send until space is freed or its storage is raised.Create and manage mailboxes

TLS(Transport Layer Security): Encryption that protects mail and sign-ins while they travel between your device and the server, and between mail servers. It stops others on the network from reading them on the way.
TTL(Time to live): How long, in seconds, other servers may cache a DNS record before checking it again. A lower TTL makes changes show up sooner.
TXT record: A DNS record that holds text. Email uses TXT records for SPF, DKIM, DMARC and domain verification.Add and verify a domain

Webmail: Reading and writing email in a web browser, with nothing to install. iResendly mailboxes have webmail at mail.iresendly.com/webmail.Using webmail