“Standard” e-Mail Adresses of Mail Servers

Every domain that supports the SMTP protocol for e-mail is required by RFC 5321 and, as early as 1982, by RFC 822, to have a set of standard addresses up and running. This means of course that these mails should not go to /dev/null :).

RFC5321, 4.5.1. Minimum Implementation:

Any system that includes an SMTP server supporting mail relaying or delivery MUST support the reserved mailbox “postmaster” as a case- insensitive local name. The requirement to accept mail for postmaster implies that RCPT commands that specify a mailbox for postmaster at any of the domains for which the SMTP server provides mail service, as well as the special case of “RCPT TO:” (with no domain specification), MUST be supported. SMTP systems are expected to make every reasonable effort to accept mail directed to Postmaster from any other system on the Internet. In extreme cases – such as to contain a denial of service attack or other breach of security – an SMTP server may block mail directed to Postmaster. However, such arrangements SHOULD be narrowly tailored so as to avoid blocking messages that are not part of such attacks.


It often is necessary to send mail to a site, without know-ing any of its valid addresses. This standard specifies a single, reserved mailbox address (local-part) which is to be valid at each site. Mail sent to that address is to be routed to a person responsible for the site’s mail system or to a person with responsibility for general site operation. The name of the reserved local-part address is: Postmaster so that “Postmaster@domain” is required to be valid. Note: This reserved local-part must be matched without sensitivity to alphabetic case.

RFC2142, MAILBOX NAMES FOR COMMON SERVICES, ROLES AND FUNCTIONS, summarizes the email addresses imposed or proposed by the RFCs around different technologies. Among various others, these sub-set of technical addresses should always be available:

  • ABUSE, Customer Relations – Inappropriate public behaviour (!)
  • NOC, Network Operations – Network infrastructure
  • SECURITY, Network Security – Security bulletins or queries
  • HOSTMASTER, DNS – RFC1033-RFC1035]
  • NEWS, NNTP – Synonym for USENET
  • WEBMASTER, HTTP – RFC 2068 (!)
  • WWW, HTTP – Synonym for WEBMASTER
  • UUCP, UUCP – RFC976
  • FTP, FTP – RFC959

So, a good and healthy /etc/aliasses configuration file should look a bit like this one:

:~# cat /etc/aliases

mailer-daemon: postmaster
postmaster: root
nobody: root
hostmaster: root
usenet: root
news: root
webmaster: root
www: root
ftp: root
abuse: root
noc: root
security: root

# Forward 'root' emails, but keep a copy in the local mail box

# More aliases....

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