term% cat index.txt DHCPD(8) System Manager's Manual DHCPD(8)
NAME
dhcpd, dhcpleases, rarpd, tftpd - Internet booting
SYNOPSIS
ip/dhcpd [-dmnprsSZ] [-f ndb-file] [-M secs] [-x netmtpt] [-Z secs] [
address n ] ...
ip/dhcpleases
ip/rarpd [-d] [-e etherdev] [-x netmtpt]
ip/tftpd [-dr] [-h homedir] [-x netmtpt]
DESCRIPTION
These programs support booting over the Internet. They should all be
run on the same server to allow other systems to be booted. Dhcpd and
tftpd are used to boot everything; rarpd is an extra piece just for
Suns.
Dhcpd runs the BOOTP and DHCP protocols. Clients use these protocols
to obtain configuration information. This information comes from at‐
tribute/value pairs in the network database (see ndb(6) and ndb(8)).
DHCP requests are honored both for static addresses found in the NDB
and for dynamic addresses listed in the command line. DHCP requests
are honored if either:
- there exists an NDB entry containing both the ethernet address of the
requester and an IP address on the originating network or subnetwork.
- a free dynamic address exists on the originating network or subnet‐
work.
A BOOTP request is honored if all of the following are true:
- there exists an NDB entry containing both the ethernet address of the
requester and an IP address on the originating network or subnetwork.
- the entry contains a bootf= attribute
- the file in the bootf= attribute is readable.
Dynamic addresses are specified on the command line as a list of ad‐
dresses and number pairs. For example,
ip/dhcpd 10.1.1.12 10 10.2.1.70 12
directs dhcpd to return dynamic addresses 10.1.1.12 through 10.1.1.21
inclusive and 10.2.1.70 through 10.2.1.81 inclusive.
Dhcpd maintains a record of all dynamic addresses in the directory
/lib/ndb/dhcp, one file per address. If multiple servers have access
to this common directory, they will correctly coordinate their actions.
Attributes come from either the NDB entry for the system, the entry for
its subnet, or the entry for its network. The system entry has prece‐
dence, then the subnet, then the network. The NDB attributes used are:
ip the IP address
ipmask the IP mask
ipgw the default IP gateway
dom the domain name of the system
fs the default Plan 9 name server
auth the default Plan 9 authentication server
dns a domain name server
ntp a network time protocol server
time a time server
wins a NETBIOS name server
www a World Wide Web proxy
pop3 a POP3 mail server
smtp an SMTP mail server
bootf the default boot file; see ndb(6)
Dhcpd will answer BOOTP requests only if it has been specifically tar‐
geted or if it has read access to the boot file for the requester.
That means that the requester must specify a boot file in the request
or one has to exist in NDB for dhcpd to answer. Dhcpd will answer all
DHCP requests for which it can associate an IP address with the re‐
quester. The options are:
d Print debugging to standard output.
f Specify a file other than /lib/ndb/local as the network data‐
base.
m Mute: don't reply to requests, just log them and what dhcpd
would have done.
M Use secs as the minimum lease time for dynamic addresses.
n Don't answer BOOTP requests.
p Answer DHCP requests from PPTP clients only.
r Mute static addresses: don't reply to requests for static ad‐
dresses, just log them and what dhcpd would have done.
s Sleep roughly 1 to 2 seconds before answering requests for
static addresses. This is used to make a server be a backup
only.
S Sleep roughly 1 to 2 seconds before answering requests for dy‐
namic addresses.
x The IP stack to use is mounted at netmtpt. The default is /net.
Z Use secs as the minimum lease time for static addresses.
Dhcpleases prints out the currently valid DHCP leases found in the
/lib/ndb/dhcp directory.
Rarpd performs the Reverse Address Resolution Protocol, translating
Ethernet addresses into IP addresses. The options are:
d Print debugging to standard output.
e Use the Ethernet mounted at /net/etherdev.
x The IP stack to use is mounted at netmtpt. The default is /net.
Tftpd transfers files to systems that are booting. It runs as user
none and can only access files with global read permission. in a file
name is replaced with the name of the booting system's file. Simi‐
larly, becomes the booting system's Ethernet MAC address and becomes
its IP address. The options are:
d Print debugging to standard output.
x The IP stack to use is mounted at netmtpt. The default is /net.
h Change directory to homedir. The default is /lib/tftpd. All
requests for files with non-rooted file names are served start‐
ing at this directory with the exception of files of the form
xxxxxxxx.SUNyy. These are Sparc kernel boot files where
xxxxxxxx is the hex IP address of the machine requesting the
kernel and yy is an architecture identifier. Tftpd looks up the
file in the network database using ipinfo (see ndb(2)) and re‐
sponds with the boot file specified for that particular machine.
If no boot file is specified, the transfer fails. Tftpd sup‐
ports only octet mode.
r Restricts access to only those files rooted in the homedir.
FILES
/lib/ndb/dhcp directory of dynamic address files
SOURCE
/sys/src/cmd/ip
SEE ALSO
ndb(6), 9boot(8), booting(8)
BUGS
Dhcpd doesn't really understand a single interface having addresses on
multiple subnets, as during renumbering of a subnet. It will only re‐
spond with addresses on the subnet of its primary IP address on that
interface.
DHCPD(8)