8 RFC Compliance and Exceptions  

RFC Compliance and Exceptions

This page lists some but not all of the RFCs which the DMail servers comply with.

In general, all of the servers in DMail comply with the relevant sections of the relevant RFCs. We will try to note any exceptions in the lists below. Feel free to contact DMail Support if you wish to query the behaviour of our servers or their RFC compliance.

DSMTP

  • 821 SIMPLE MAIL TRANSFER PROTOCOL (SMTP)
  • 822 STANDARD FOR THE FORMAT OF ARPA INTERNET TEXT MESSAGES
    Exception 1: forward slashes '/' not supported in local usernames, but are supported for non-local users.
    Exception 2: escape characters not supported in local usernames, but are supported for non-local users.
    Exception 3: quoted usernames support added in version 2.7q
     
  • 1651 (ESMTP) SMTP Service Extensions
  • 1854 (ESMTP) SMTP Service Extension for Command Pipelining
  • 1891 (ESMTP) SMTP Service Extension for Delivery Status Notifications
  • 2487 (ESMTP) SMTP Service Extension for Secure SMTP over TLS
  • 2505 Anti-Spam Recommendations for SMTP MTAs
  • 2554 (ESMTP) SMTP Service Extension for Authentication

DPOP

  • 1939 Post Office Protocol - Version 3

General

  • 1321 The MD5 Message-Digest Algorithm
  • 2195 IMAP/POP AUTHorize Extension for Simple Challenge/Response


Exceptions

  1. Exception 1: We have decided that local usernames may not contain forward slashes '/', because of the ambiguity with drop file names. Connections giving a username containing a slash for a local domain will get a "RCPT not OK" response. Versions 2.7i and above pass on messages to non local domains even if they contain a forward slash.
  2. Exception 2: Similarly, we have decided that local usernames may not contain escape characters e.g. '\"'. Connections giving a username containing a slash for a local domain will get a "RCPT not OK" response as they will hit the exception above. Versions 2.8n and above pass on messages to non local domains even if they contain ANY escaped character.
  3. Exception 3: Versions 2.7q and above are compliant in respect to quoted usernames, e.g.
    "bob"@domainx.com will result in mail going to the local user bob if domainx.com is local and will be passed through unchanged if destined for a non-local domain.