rarpd.8c

<B>Digital的Unix操作系统VAX 4.2源码</B>

.TH rarpd 8c
.SH Name
rarpd \- reverse address resolution protocol (RARP) daemon
.SH Syntax
.B /usr/etc/rarpd 
[
.I interface 
]
[
.B \-v
]
[
.B \-n
]
[
.B \-f
.I filename
]
.\"
.SH Description
.NXR "rarpd program" "description"
.NXR "Reverse Address Resolution Protocol Daemon" "rarpd program"
The 
.PN rarpd
daemon maps the Ethernet address of a machine
to the machine's Internet Protocol (IP) address.
.PP
When 
.PN rarpd
is invoked, it reads the 
.PN /etc/ethers
file (by default) and waits to process a RARP request.
The 
.PN /etc/ethers
file is checked every ten minutes for any changes.  If the file
has been modified, 
.PN rarpd
reads it again. You can disable this feature
with the
.PN \-n
option. You can force a scan of the 
.PN /etc/ethers 
file by sending the 
.PN rarpd
daemon a SIGHUP signal.  See
.MS signal 3 
for more information on SIGHUP.
.PP
The format of the 
.PN /etc/ethers
file is described in
.MS ethers 5 .
You can specify a file other than 
.PN /etc/ethers
with the
.PN \-f 
option.  The 
.I interface 
is the network interface on
which the 
.PN rarpd
daemon should listen. The command
.PN "netstat \-i"
shows the correct interface or interfaces for your system.
The 
.PN rarpd
daemon uses the first interface it finds, if you do not specify
an interface.  See the 
.MS netstat 1
reference page for more information.
.PP
Because the 
.PN rarpd
daemon has been implemented with the Ethernet Packet Filter (see
.MS packetfilter 4 ),
you must configure your kernel
with the packet filter option in order for 
.PN rarpd
to function properly.
The packet filter detects RARP broadcast packets and passes
them to
.PN rarpd
for processing. The filter priority
for rarpd is set to 28. 
.PP
All messages from the 
.PN rarpd
daemon are directed to
.PN  syslog .
.SH Options
.NXR "rarpd program" "options"
.IP \fIinterface\fR 15
Specifies the system's network interface.
.IP \-v 15
Causes 
.PN rarpd 
to operate in verbose mode. This option logs details of RARP
to 
.PN syslog .
The instance of a RARP request and its response are
also logged.
.IP \-n 15
Disables checking of the
.MS ethers 5
file.  By default, 
.PN rarpd
checks the
.PN  ethers
file 
once every ten minutes, and, if the file was modified,
.PN rarpd
rereads the file.
If you specify the
.PN \-n
option 
.PN rarpd
scans the 
.PN /etc/ethers 
file once at startup time.
.IP "\-f \fIfilename\fR" 15
Reads an alternate Ethernet address file. 
.SH Restrictions
The 
.PN rarpd
ignores all ARP requests sent encapsulated
within a RARP packet. You should make all ARP request using the
.PN arp 
command.
.PP
The machine for which an IP address is being requested must
be present in the server's 
.PN /etc/hosts 
file.
.SH Diagnostics
The following message is logged to 
.PN syslog
if the Packet Filter is not configured in your kernel:
.EX
Packet Filter is not configured in /vmunix
.EE
The following messages are printed to your screen if the
Packet Filter is not configured in your kernel:
.EX
rarpd: cannot find symbol Pfilt_read in /vmunix
option PACKETFILTER does not appear to be configured in 
       your kernel.
.EE
.SH Files
.TP 20
.PN /etc/ethers
Database that maps Ethernet addresses to hostnames
.SH See Also
ethers(3n), packetfilter(4), ethers(5), hosts(5), arp(8c), ifconfig(8c), syslog(8c)
.br
.I "The Packet Filter: An Efficient Mechanism for User-Level Network Code"