DHCPD(8)DHCPD(8)

NAME

dhcpd, dhcp6d, dhcpleases, rarpd, tftpd – Internet booting

SYNOPSIS

ip/dhcpd [-dmnprsSZ] [-h homedir] [-f ndbfile] [-M secs] [-x netmtpt] [-Z secs] [ address n ] ...

ip/dhcpleases

ip/dhcp6d [-d] [-f ndbfile] [-x netmtpt]

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, dhcp6d 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 attribute/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 subnetwork.

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 addresses 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 precedence, 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 file 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)  

tftp

the TFTP server to fetch bootf from  

rootpath

the NFS root for unix machines  

rootserver

the NFS server used with rootpath  

vendor

Specific vendor attribute for dhcp and bootp  

Dhcpd will answer BOOTP requests only if it has been specifically targeted 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 requester. The options are:

d

Print debugging to standard output.  

h

Change directory to homedir. The default is /. This should match the homedir setting of tftpd so that the existence check of non-rooted file names is consistent.  

f

Specify a file other than /lib/ndb/local as the network database.  

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 addresses, just log them and what dhcpd would have done.  

s

Sleep 2 seconds before answering requests for static addresses. This is used to make a server be a backup only.  

S

Sleep 2 seconds before answering requests for dynamic 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.  

Dhcp6d provides DHCPv6 service for IPv6 clients. Only network boot and DNS parameters are supported.

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. 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 /. All requests for files with non-rooted file names are served starting at this directory. This needs to be consistent with the homedir setting of dhcpd. Tftpd supports 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), booting(8)