This guide details the allowed and prohibited characters when creating an email address (up to 64 characters) in an Infomaniak Mail Service.

Introduction

• The allowed characters differ depending on whether they appear before or after the at symbol @. For example, in nom-utilisateur.mail@nom-domaine.xyz:
  • Before the at symbol: the nom-utilisateur.mail part corresponds to the username.
  • After the at symbol: the nom-domaine.xyz part corresponds to the domain name.
• To learn about the possibilities offered at the domain name level (the part after the at symbol @), see this other guide.

Part before the at symbol: nom-utilisateur.mail

The RFC 5321 and RFC 5322 standards define the general syntax of email addresses. However, email providers – including Infomaniak – apply additional restrictions to ensure security, consistency, and compatibility with most software/email clients.

For example, an address such as -@exemple.com is syntactically valid according to RFC 5322, but is not accepted when created on Infomaniak servers.

These additional rules help to:

• prevent abuse (spam, malicious automation, etc.);
• comply with naming conventions (an identifier consisting only of - does not make sense);
• to ensure compatibility with email software/clients that handle certain address formats poorly.

In summary: RFC 5322 defines what is syntactically possible, but each server determines what is actually usable in practice.

Allowed characters before the at sign

The following characters can be used in the part before the at sign of an Infomaniak email address:

Forbidden characters before the at sign

The following characters (at sign, exclamation mark, hash, dollar, percent, caret, ampersand, asterisk, parenthesis, equals sign, bracket, chevron, comma, quotation marks, semicolon, question mark…) cannot be used to create an Infomaniak email address: