FAQ

Email is the oldest and most widely used Internet service. Email stands for "electronic Mail" and is used for exchanging digital messages. It consists of an email header (the head) and an email body (the actual content).

Emails are now primarily transmitted via SMTP and IMAP or POP3. Sender or recipient addresses look like this: info@mail.de. Here, "info" is the so-called local part and "mail.de" the domain part.

Email communication involves several components: Mail User Agents, Mail Transfer Agents, and Mail Delivery Agents. Mail User Agents are the familiar email clients used for reading, composing, sending, and receiving emails. They cannot communicate directly with each other. When an email is sent via a Mail User Agent, it first reaches a Mail Transfer Agent (MTA), typically an SMTP server that accepts and forwards emails. If the recipient address does not belong to the same domain part, the email is forwarded to the responsible MTA for that domain and then to the Mail Delivery Agent (MDA), usually an IMAP or POP3 server accessible via the recipient's Mail User Agent.

An email attachment can be thought of like an enclosure in a letter. In email, it's a file sent from sender to recipient, enabled by the MIME protocol (Multipurpose Internet Mail Extensions), which allows audio, video, and binary files to be transmitted without converting to 7-bit ASCII (the original email format).

Note whether the recipient has the appropriate program to open the file and the maximum allowed attachment size of the email service (for both sender and recipient). If emails including attachments are too large and cannot be delivered, a bounce message is returned — an automatic error notification from the mail server for undeliverable emails.

Email filters simplify handling incoming messages. They can filter by sender, recipient, subject, CC, BCC, and content parts, moving emails to separate folders. Emails from specific senders can also be marked as spam or unwanted advertising, so future emails are filtered, moved, or deleted. Filters can also enable forwarding or automatic replies for matching conditions.

The process for creating filters varies by provider — typically found under "Settings" or "Einstellungen".

An email consists of a header (head lines) and body (message content). The header includes sender, send date, and possibly recipient/content info. For technical delivery, envelope sender and envelope to are used instead.

Email clients typically display: Sender, Recipient, CC, Subject, Creation time.

Addresses: Local-Part@Domain-Part (e.g., info@mail.de).

CC (Carbon Copy): Visible copy to additional recipients for information — not the primary addressee. CC addresses visible to all.

BCC (Blind Carbon Copy): Invisible to recipients — for information or control (e.g., superiors).

An email collection service automatically fetches emails from multiple mailboxes of different providers, allowing centralized management without checking each provider separately.

An email signature contains sender details, typically at the message end.

Since 01/01/2007, merchants under HGB and employees must include at least: Sender's full name, Company name/seat/legal form, Managing directors/supervisory board chair names, Commercial register number/register court, VAT ID.

Legal basis: §37a HGB, §35a GmbHG, §80 AktG.

Phone/fax/email/website not mandatory but common and helpful in practice.

Unlike plain text emails, HTML emails support different font sizes, types, and colors. Originally not intended for email → past security vulnerabilities (worms, tracking pixels). Issues improved significantly, but HTML emails are still considered less secure than plain text.

Simple Mail Transfer Protocol – Internet protocol primarily for injecting or forwarding emails (sending).

Post Office Protocol 3 – Protocol to retrieve emails from a server. Emails downloaded, stored locally, usually deleted from server. Most services now offer keeping on server. No constant connection needed; offline processing possible. Clients: Outlook Express, Apple Mail, Mozilla Thunderbird. Read-only access; sending via SMTP/other. Recommendation: IMAP over POP3 for bidirectional sync.

Internet Message Access Protocol – Allows access and management of emails on server (emails stay there). Enables current state/folder sync across multiple clients. No local storage needed → higher security (delete dangerous emails on server). Connection can be encrypted via SSL/TLS (activate in client and server). Clients: Outlook Express, Apple Mail, Thunderbird — full mailbox/folder sync. Bidirectional: Client changes reflected on server and other devices. Access to emails; sending via SMTP/other.

Mail User Agents/Email Clients for reading/composing/sending/receiving emails. Retrieve via POP3 (download) or IMAP (server access). Send to SMTP server (MTA). Setup: SMTP/IMAP/POP3 server names + username/password.

Usually emails exchanged between two parties, but sometimes reaching multiple people makes sense. Webmail/client limits reached with large recipients; replies must go to all. Server-side mailing lists used: One address reaches all members, addresses hidden/protected. List server checks sender/content against filters, then forwards. Self-subscribe/unsubscribe via interface if allowed.

Push Email: Server immediately forwards new emails to client. Server initiates connection on arrival. Opposite of polling (client fetches at login/interval/manual). Especially useful for mobile (no delay, no manual check). Also possible via IMAP-Idle (permanent connection), but data-intensive on time-based mobile plans.

SSL (Secure Sockets Layer) or successor TLS (Transport Layer Security) are encryption protocols for secure data transfer on the web (HTTPS, padlock icon). Today TLS 1.3 is standard (SSL obsolete).

Prevents third parties from viewing/storing/altering sensitive data (e.g., bank details). Browser checks certificate validity/ownership. Uses asymmetric then symmetric encryption for security. Higher security needs more computing power → often only for sensitive pages. For banking/shopping: Use TLS 1.2/1.3; encryption from 128 bit considered secure (earlier 112 bit sufficient).

Webmail allows email access from any internet-connected computer (device-independent). Unlike clients (tied to installed/configured device), webmail accessible anywhere online. Setup: Go to provider homepage → login with username/password → manage mailbox.

Many providers exist with big differences. Consider when choosing: Spam protection, storage space, max attachment size (send/receive), usability, virus protection, extras (SMS/fax/voicemail), IMAP, email collection service.