pathalias.1 (2010 09)

p
pathalias(1) pathalias(1)
NAME
pathalias - electronic address router
SYNOPSIS
pathalias [-ivcDf][-l host ][
-d link ][-t link ][files ]
DESCRIPTION
pathalias computes the shortest paths and corresponding routes from one host (computer system) to
all other known, reachable hosts. pathalias reads host-to-host connectivity information on standard
input or in the named files, and writes a list of host-route pairs on the standard output.
Options
pathalias recognizes the following options and command-line arguments:
-i Ignore case: map all host names to lowercase. By default, case is significant.
-c Print costs. Print the path cost (see below) before each host-route pair.
-v Verbose. Report some statistics on the standard error output.
-D Terminal domains. Domain members are terminal.
-f First hop cost. The printed cost is the cost to the first relay in a path instead of the cost
of the path itself; implies (and overrides) the -c option.
-l host Set local host name to host . By default, pathalias discovers the local host name in a
system-dependent way.
-d link Declare a dead link, host, or network (see below). If link is of the form
host1!host2,
the link from host1 to host2 is treated as an extremely high cost (i.e.,
DEAD) link. If link
is a single host name, that host is treated as dead and is used as an intermediate host of
last resort on any path. If link is a network name, the network requires a gateway.
-t link Trace input for link, host, or network on the standard error output. The form of link is
as above.
The public domain version of
pathalias includes two undocumented options that are briefly described
in the Special Options section below.
Input Format
A line beginning with white space continues the preceding line. Anything following
# on an input line is
ignored.
A list of host-to-host connections consists of a ‘‘from’’ host in column 1, followed by white space, followed
by a comma-separated list of ‘‘to’ hosts, called links . A link may be preceded or followed by a network
character to use in the route. Valid network characters are
! (default), @,
:, and %. A link (and network
character, if present) may be followed by a ‘‘cost’’ enclosed in parentheses. Costs can be arbitrary arith-
metic expressions involving numbers, parentheses,
+, -, *, and /. Negative costs are prohibited. The fol-
lowing symbolic costs are recognized:
LOCAL 25 (local-area network connection)
DEDICATED 100 (high speed dedicated link)
DIRECT 200 (toll-free call)
DEMAND 300 (long-distance call)
HOURLY 500 (hourly poll)
EVENING 2000 (time restricted call)
DAILY 5000 (daily poll, also called
POLLED)
WEEKLY 30000 (irregular poll)
In addition,
DEAD is a very large number (effectively infinite), and HIGH and LOW are −5 and +5
respectively, for baud-rate or quality bonuses/penalties, and FAST is -80, for adjusting costs of links that
use high-speed (9.6 Kbaud or more) modems. These symbolic costs represent an imperfect measure of
bandwidth, monetary cost, and frequency of connections. For most mail traffic, it is important to minim-
ize the number of hosts in a route, thus, e.g. , HOURLY is far greater than DAILY divided by 24. If no
cost is given, a default of 4000 is used.
For the most part, arithmetic expressions that mix symbolic constants other than
HIGH, LOW, and FAST
make no sense. For example, if a host calls a local neighbor whenever there is work, and additionally
polls every evening, the cost is DIRECT, not DIRECT+EVENING.
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1