varspoolmail

Varspoolmail is a term used to refer to the local mail spool on Unix-like systems—the directory or structure where incoming mail is stored before it is delivered to the recipient’s mailbox. It is a component of the mail delivery pipeline used by mail transfer agents (MTAs) such as Postfix, Sendmail, or Exim, and by local delivery agents and mail clients.

Location and mailbox formats vary by system and MTA. Traditional configurations use /var/spool/mail or /var/mail, with one mailbox file per user, typically in the mbox format. Modern setups may employ the Maildir format, where each user has a Maildir directory containing subdirectories such as new, cur, and tmp. The Maildir structure can reside under the spool path or within the user’s home directory, depending on the administrator’s choice.

Access and permissions are tightly controlled. Spool files are usually owned by root with the mail group (for example, root:mail) and have restrictive permissions to prevent unauthorized access. Local users access their mail through a local mail user agent (MUA) that reads from the spool or from a Maildir managed by the MTA/MDA. Remote clients typically access mail via IMAP or POP servers that read from the same storage.

Administration and maintenance involve ensuring correct delivery paths, managing spool size, and verifying that the MTA and MDA are configured to deliver to the intended mailbox format. Security considerations include preventing unauthorized access and removing delivered messages in a timely manner to avoid spool overflow.

See also: mailbox, mbx, mbox, Maildir, Postfix, Dovecot.