NAME

paths − smail routing database

DESCRIPTION

The paths file is the routing database for smail. Each line of the file provides routing information to either a host or to a domain. Each line should have either two or three tab-separated (ascii 0x9) fields.  The format of each line in the paths file is:

key  route   [cost]

The key field is the key on which searches are performed.  Typically, this is either a UUCP host name or a domain name.  The smail program uses a binary search algorithm when searching the database, so the keys must be sorted in ascending order.  Case is ignored when searching, so the keys should be converted to lowercase before sorting (see lcasep(8) and ­pathproc(8)). 

The route field is a printf string that details the route that mail to the key should take.  See the pathalias documentation for details. 

The optional cost field is used by smail to determine whether to simply queue outbound UUCP mail, or whether to attempt immediate delivery (usually by invoking uucico). If the cost field is present, and the value is at or below smail’s queueing threshold, then the mail will be queued and an attempt at immediate delivery will be made. This will speed mail delivery between hosts who enjoy an inexpensive uucp link, such as a hardwired line or some other low-cost transport medium, while allowing mail sent over more expensive media to accumulate before transmission.  If the field is absent, the cost defaults to a value above the queueing threshold. The default value for the queueing threshold is equal to the pathalias cost DEDICATED+LOW.  Thus, direct links with a cost of DEDICATED+LOW or less will see immediate delivery, while the others are queued for later delivery. 

Example

Here is a sample paths file for a small host, such as a PC, that does not want to maintain complete routing information.  It illustrates most of the aspects of the paths file.  Assume that the PC’s name is mypc and that it is in domain .mydomain. Also assume that it has a dedicated link to a smart host named bighub, and that bighub’s administrator has given mypc permission to use bighub as a mail relay.  Lastly, assume that mypc has a dialed on demand link to another computer named friend.

pathalias input:
 mypc = .mypc.mydomain
 mypc friend(DEMAND), bighub(DEDICATED)
 smart-host = bighub

Here is a paths file produced by pathalias −f inputfile|pathproc:

.mypc.mydomain %s0
bighub bighub!%s95
friend friend!%s300
mypc %s    0
smart-host bighub!%s    95

SEE ALSO

lcasep(8), pathproc(8), smail(8) in the INTERACTIVE UNIX System User’s/System Administrator’s Reference Manual.
pathalias by Peter Honeyman. 

ADDED VALUE

This entry, supplied by INTERACTIVE Systems Corporation, is an extension of UNIX System V. 

\*U  —  Version 1.0