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Overview

This document lists all restrictions on cPanel & WHM usernames.

Basic restrictions

The following list describes a basic set of rules to follow when you create a username:

  • Only uses the a-z, 0-9, or '.' characters.

    Warning:

    We strongly recommend that you do not use a period in the username because it may cause conflicts in MySQL®.

  • 16 characters or fewer.
  • Cannot begin with a digit (0-9) or a period (.)
  • Cannot start with the characters test
  • Cannot end with the characters assword

Special cases

  • You cannot create a username with the hyphen character (-), but you can change an account's name to use a hyphen when you transfer that account to another system.
  • If you wish to allow usernames over eight characters in length, set the LONGUSERS: 1 environment variable in the /var/cpanel/whm/nvdata/root.yaml file.
  • If you plan to use MySQL or PostgreSQL as a database engine, the first eight characters must be unique on the system.

    Note:

    You can disable database prefixing with the Add prefix to names of new databases and database users option in the SQL section of WHM's Tweak Settings interface (WHM >> Home >> Server Configuration >> Tweak Settings).

  • If you wish to allow leading digits in a username, create the /etc/allowstupidstuff touchfile.

Reserved names and restricted aliases

cPanel & WHM checks the following files to determine whether to reserve or restrict a username or alias:

  • /usr/local/cpanel/Cpanel/Validate/Username/Core.pm
  • /etc/aliases
  • /etc/localaliases

Additional documentation