+++ /dev/null
-<!doctype linuxdoc system>
-
-<article>
-
-<title>ARPD Daemon
-<author>Alexey Kuznetsov, <tt/kuznet@ms2.inr.ac.ru/
-<date>some_negative_number, 20 Sep 2001
-<abstract>
-<tt/arpd/ is daemon collecting gratuitous ARP information, saving
-it on local disk and feeding it to kernel on demand to avoid
-redundant broadcasting due to limited size of kernel ARP cache.
-</abstract>
-
-
-<p><bf/Description/
-
-<p>The format of the command is:
-
-<tscreen><verb>
- arpd OPTIONS [ INTERFACE [ INTERFACE ... ] ]
-</verb></tscreen>
-
-<p> <tt/OPTIONS/ are:
-
-<itemize>
-
-<item><tt/-l/ - dump <tt/arpd/ database to stdout and exit. Output consists
-of three columns: interface index, IP address and MAC address.
-Negative entries for dead hosts are also shown, in this case MAC address
-is replaced by word <tt/FAILED/ followed by colon and time when the fact
-that host is dead was proven the last time.
-
-<item><tt/-f FILE/ - read and load <tt/arpd/ database from <tt/FILE/
-in text format similar dumped by option <tt/-l/. Exit after load,
-probably listing resulting database, if option <tt/-l/ is also given.
-If <tt/FILE/ is <tt/-/, <tt/stdin/ is read to get ARP table.
-
-<item><tt/-b DATABASE/ - location of database file. Default location is
-<tt>/var/lib/arpd/arpd.db</tt>.
-
-<item><tt/-a NUMBER/ - <tt/arpd/ not only passively listens ARP on wire, but
-also send brodcast queries itself. <tt/NUMBER/ is number of such queries
-to make before destination is considered as dead. When <tt/arpd/ is started
-as kernel helper (i.e. with <tt/app_solicit/ enabled in <tt/sysctl/
-or even with option <tt/-k/) without this option and still did not learn enough
-information, you can observe 1 second gaps in service. Not fatal, but
-not good.
-
-<item><tt/-k/ - suppress sending broadcast queries by kernel. It takes
-sense together with option <tt/-a/.
-
-<item><tt/-n TIME/ - timeout of negative cache. When resolution fails <tt/arpd/
-suppresses further attempts to resolve for this period. It makes sense
-only together with option <tt/-k/. This timeout should not be too much
-longer than boot time of a typical host not supporting gratuitous ARP.
-Default value is 60 seconds.
-
-<item><tt/-R RATE/ - maximal steady rate of broadcasts sent by <tt/arpd/
-in packets per second. Default value is 1.
-
-<item><tt/-B NUMBER/ - number of broadcasts sent by <tt/arpd/ back to back.
-Default value is 3. Together with option <tt/-R/ this option allows
-to police broadcasting not to exceed <tt/B+R*T/ over any interval
-of time <tt/T/.
-
-</itemize>
-
-<p><tt/INTERFACE/ is name of networking inteface to watch.
-If no interfaces given, <tt/arpd/ monitors all the interfaces.
-In this case <tt/arpd/ does not adjust <tt/sysctl/ parameters,
-it is supposed user does this himself after <tt/arpd/ is started.
-
-
-<p> Signals
-
-<p> <tt/arpd/ exits gracefully syncing database and restoring adjusted
-<tt/sysctl/ parameters, when receives <tt/SIGINT/ or <tt/SIGTERM/.
-<tt/SIGHUP/ syncs database to disk. <tt/SIGUSR1/ sends some statistics
-to <tt/syslog/. Effect of another signals is undefined, they may corrupt
-database and leave <tt/sysctl/ parameters in an unpredictable state.
-
-<p> Note
-
-<p> In order to <tt/arpd/ be able to serve as ARP resolver, kernel must be
-compiled with the option <tt/CONFIG_ARPD/ and, in the case when interface list
-is not given on command line, variable <tt/app_solicit/
-on interfaces of interest should be set in <tt>/proc/sys/net/ipv4/neigh/*</tt>.
-If this is not made <tt/arpd/ still collects gratuitous ARP information
-in its database.
-
-<p> Examples
-
-<enum>
-<item> Start <tt/arpd/ to collect gratuitous ARP, but not messing
-with kernel functionality:
-
-<tscreen><verb>
- arpd -b /var/tmp/arpd.db
-</verb></tscreen>
-
-<item> Look at result after some time:
-
-<tscreen><verb>
- killall arpd
- arpd -l -b /var/tmp/arpd.db
-</verb></tscreen>
-
-<item> To enable kernel helper, leaving leading role to kernel:
-
-<tscreen><verb>
- arpd -b /var/tmp/arpd.db -a 1 eth0 eth1
-</verb></tscreen>
-
-<item> Completely replace kernel resolution on interfaces <tt/eth0/
-and <tt/eth1/. In this case kernel still does unicast probing to
-validate entries, but all the broadcast activity is suppressed
-and made under authority of <tt/arpd/:
-
-<tscreen><verb>
- arpd -b /var/tmp/arpd.db -a 3 -k eth0 eth1
-</verb></tscreen>
-
-This is mode which <tt/arpd/ is supposed to work normally.
-It is not default just to prevent occasional enabling of too aggressive
-mode occasionally.
-
-</enum>
-
-</article>
-
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