How the file names are given to mails in centos

In CentOS, the file names of emails are typically generated by the MTA (Mail Transfer Agent) software, such as Postfix or Sendmail. The exact method of generating file names can vary depending on the MTA software and its configuration.

Here are some common ways that file names are generated for emails in CentOS:

1. Postfix: Postfix uses a combination of the sender's email address, the recipient's email address, and a timestamp to generate a unique file name for each email. The file name typically follows the format YYYYMMDD.HHMMSS.SENDER.QUEUEID, where:
   • YYYYMMDD is the date in YYYYMMDD format
   • HHMMSS is the time in HHMMSS format
   • SENDER is the sender's email address
   • QUEUEID is a unique identifier for the email
2. Sendmail: Sendmail uses a similar approach to Postfix, but with a slightly different format. The file name typically follows the format YYYYMMDD.HHMMSS.SENDER.QUEUE, where:
   • YYYYMMDD is the date in YYYYMMDD format
   • HHMMSS is the time in HHMMSS format
   • SENDER is the sender's email address
   • QUEUE is a unique identifier for the email
3. Other MTAs: Other MTAs, such as Exim or Qmail, may use different methods to generate file names for emails. However, the general approach is similar, using a combination of the sender's email address, the recipient's email address, and a timestamp to generate a unique file name.

In CentOS, the file names of emails are typically stored in the /var/spool/mail directory, which is the default location for email spools. The file names are usually in the format described above, but may vary depending on the MTA software and its configuration.

It's worth noting that the file names of emails are not always human-readable, and may contain special characters or non-ASCII characters. Additionally, the file names may change over time as emails are delivered, bounced, or deleted.