alias file

The alias file is used to map LOCAL names to other names. The target names may be either local or remote. Additionally, a single input name may produce multiple output messages. Thus, typical uses for the alias file are:

converting one local name to another,
converting a local name to a remote name,
exploding a mail message so that it is passed on to several recipients.

The aliasname is a local username or area; that is, it does not contain an "@" symbol. When the alias file is processed, if the destination of the message matches the aliasname precisely, then the mail is redirected to ALL of the aliased recipients. Note that alias records are of the form:

```
aliasname    dest1 dest2 ... destn
```

Each field entry is separated by whitespace. Each destination may be one of:

a local area name
a AX.25 formatted name
a TCP/IP formatted name

Each record is separated by a newline.

Mail transport within a single NOS system is performed through the SMTP client/server mechanism. Scanning the alias file is performed by the SMTP server. The SMTP timer (which initiates the SMTP client) is kicked whenever the mailbox or SMTP server queues something for delivery. The result of these facts is that as soon as a piece of mail is entered to the mailbox, the SMTP client is kicked and attempts to deliver the mail (which has already been scanned by the rewrite mechanism - see RewriteFile). If the mail is local to the NOS system (i.e. no "@" sign in the address), then the alias file is scanned and the name mappings take place. As the alias file is scanned only once (see below), this does not result in an infinite recursion. A few lines in the /alias file might look something like:

bdale   bdale@n3eua
local   fred@k0yum bdale@n3eua bill@ai0c.ampr.org n5op@n5op jim@k0jtz n0esg@n0esg
g4bki   g4bki@gb7bil.ampr.org

SMTP delivers to each of the individual addresses in the style in which they are entered in the alias file. If the system does not know how to deliver one of the new addresses, then it will send it to the SMTP gateway station defined by the 'smtp gateway' command.