PMDF addresses can use certain non-standard, but sometimes useful, formats. These formats are not part of RFC 822 and, as such, constitute non-standard extensions to RFC 822. These extensions are:

• If an address does not contain an at sign, @, and hence does not contain the name of a destination system, then the name of the local host is used for the destination system.³ Note that the elimination of the at sign can in turn eliminate the need for double quotes. For example, the address

  IN%user

  is interpreted as

  IN%"USER@local-host"

  where local-host is the local host name. ⁴ As an example, try sending mail to yourself, and, when you receive the message, look at the From: address. For instance, if the local host name is example.com and your username is mrochek, then the address specification in%mrochek will be interpreted as in%"MROCHEK@example.com". Forms such as

  IN%"user1, user2, user3"

  are also allowed. (user1 , user2, and user3 are not subject to separate logical name translation in this case.) Such an address specification is equivalent to

  IN%"user1@local-host, user2@local-host, user3@local-host"

  
  

• Source-routed addresses without surrounding angle brackets are accepted even though RFC 822 does not formally allow such syntax. For example,

  IN%"@cunyvm.cuny.edu:fresnel@kitvax"

  is treated as

  IN%"<@cunyvm.cuny.edu:fresnel@kitvax>"

  
  

• Personal names can contain periods and other punctuation characters without being surrounded by double quotes, even though the quotes are called for by RFC 822. For example,

  IN%"Augustin J. Fresnel <fresnel@kitty.farm.org>"

  is treated as

  IN%"'Augustin J. Fresnel' <fresnel@kitty.farm.org>"

  
  

• IBM NOTES format addresses are accepted. These are addresses of the form

  IN%"user AT host"

  and are converted to

  IN%"user@host"

  
  

• Addresses of the form

  IN%"user@host1@host2"

  are converted to

  IN%"user%host1@host2"

  
  

• Addresses of the form

  IN%"@host:user"

  are converted to

  IN%"@host:user@localhost"

  
  

• So-called "DECnet-style" addresses are accepted and converted into RFC 822 format. That is, addresses of the form

  IN%system::user

  are converted to

  IN%"USER@SYSTEM"

  Note the forced conversion to upper case. This conversion is done by VMS MAIL and cannot be eliminated or undone. This address format is discouraged for this reason; RFC 822 mandates preservation of case in the local part (the part to the left of the at sign) of all addresses. In addition, system is translated as a logical name. Multiple routing systems can be specified; e.g., an address such as

  IN%system1::system2::system3::user

  is converted to

  IN%"USER%SYSTEM3%SYSTEM2@SYSTEM1"

  Note Surrounding double quotes can not be used with DECnet-style addresses. This restriction is imposed by VMS MAIL, not PMDF.

In all cases PMDF reformats the addresses to comply with RFC 822, so no illegal addresses are passed to other mail systems.