client.pcy(4)client.pcy(4)NAMEclient.pcy - BOOTP and DHCP client policy
DESCRIPTION
The client.pcy file is a text database, read by the joinc daemon on
startup, which governs the behavior of BOOTP and DHCP clients. If the
JOINCONFIG variable is present in the joinc environment, it is taken to
be the directory where client.pcy is housed; otherwise joinc searches
the /etc/join directory. Defaults exist for all parameters and
switches, so it is not an error if the file does not exist.
FORMAT
Blank lines are ignored. The number sign (#) introduces a comment
which continues to the next newline. Each new policy option must begin
and end on a separate line. Policy options are introduced by a key‐
word, and may be Boolean, or may take a value separated from the key‐
word by whitespace (but not a newline). If an option is present more
than once, only the value attached to the last occurrence takes effect
- earlier value(s) are forgotten.
KEYWORDS AND VALUES
If no DHCP responses are heard and this flag is set, the client uses
any BOOTP response in the configuration. In this scenario, the client
does not renew, rebind, expire, or release its IP address lease. In
other words the client is given what is effectively an infinite lease.
Although the client accepts BOOTP responses, it only sends DHCP pack‐
ets. There is no guarantee that BOOTP servers which hear these packets
will respond, since they may become confused by the presence of DHCP
data within the packet. When the client receives an IP address from
the server, it performs an ARP on the local network to verify that no
other client is using the address. If the client receives no reply
after seconds expires, it assumes that it may use the address.
Default: 2 seconds. The client's class ID. Consult RFC1541 for
details. Use a client identifier other than the MAC address. Cur‐
rently setting client_id tells the DHCP client daemon to use a concate‐
nation of the MAC address and the interface name as the client ID. The
MAC address is in internal form, not the readable, colon-separated
string. You must use this option when configuring a client with multi‐
ple interfaces and where the client's MAC address is the same on each
interface (SUN hardware for example). The DHCP server grants the
client permission to use an IP address for a fixed period of time
(which may be infinite). In the language of DHCP, the client is granted
a "lease" on the IP address. With this parameter, the client may
request a lease of a particular duration, although servers are not
bound to honor the request. If the client does not care, seconds should
be set to zero; if an infinite lease is required, to minus one, -1.
Otherwise specify in seconds the lease duration required.
Default: 0 This parameter is subtly different from the number of
retries a client will make as part of an exponential broadcast retry
backoff. Rather it is the number of separate attempts the client will
make to contact a server, assuming that replies are received, but that
the client, for one reason or another, rejected those replies.
Default: 2 Clients are required by the DHCP protocol to implement an
exponential retransmission and backoff when broadcasting discover or
request packets. The array of values specifies how long the client
should wait for replies before timing out and retrying the broadcast.
Each time the client sends a DHCP protocol packet, it waits for
a response until a timeout occurs as specified by a member of
this array (in seconds). If a timeout has occurred, the packet
is retransmitted with the same XID (see RFC 1541) and the time‐
out is set to the next positive number in the comma-separated
list. The last element in the list is negative or zero. After
all specified timeouts have been tried, the next action depends
on options to the dhcpconf program. One option is to fail;
another is to retry forever. See dhcpconf(8) for further infor‐
mation. If the last value is negative, DHCP suspends configura‐
tion of the interface for an amount of time given by the nega‐
tive number terminating the array. During this time, the inter‐
face is considered idle; the client is not expecting responses
destined for the interface and will ignore any that arrive.
When the idle time is over, the client begins retransmitting
with a timeout given by the first element in the array and a new
XID. If the last value is zero, the client continues to use the
same XID and timeout of the last positive value in the array.
Default: 4,8,16,32,0 If there is no reply to DHCP, and
use_saved_config is set, then use the configuration stored in
<interface>.cf from a previous invocation of the protocol pro‐
viding the lease is still valid. The DHCP protocol requires
clients to delay a random time interval on booting, and after
each timeout, before broadcasting to the net. This is to prevent
network "flooding" in the event that many clients try to config‐
ure simultaneously (say after a sitewide power-up). This parame‐
ter is the maximum delay that the client will tolerate. The
actual delay is randomized from zero to seconds. Note that on
each timeout the client will also delay, and that the second and
subsequent delays are also random, and need not be the same as
the first.
Default: 10 seconds. There may be many instances of the request
keyword, each with a different parameter_name. Each parameter
that is configurable through DHCP and the server extensions is
identified by a unique parameter. Limited size of DHCP packets
dictates that a client should not request data which it cannot
use. However, different DHCP servers, or different server poli‐
cies may dictate that a server return more configuration than a
client requested. For a description of the meaning of the vari‐
ous parameters, consult RFC1542 and others to which it refers.
Valid options follow. The first group are DHCP generic:
all_sub‐
nets_are_local
arp_cache_time‐
out
boot_file
boot_file_server
boot_size
broad‐
cast_address
cookie_server
default_ip_time-
to-
live
dns_domain_name
dns_servers
eth‐
er‐
net_encap‐
su‐
la‐
tion
exten‐
sions_path
home_direc‐
tory
host_name
impress_server
inter‐
face_mtu
ip_for‐
ward‐
ing
keepalive_garbage
lease_time
log_server
lpr_server
mask_sup‐
plier
max‐
i‐
mum_data‐
gram_reassem‐
bly_size
merit_dump_file
name_server
net‐
bios_data‐
gram_dis‐
tri‐
bu‐
tion_server
net‐
bios_name_server
net‐
bios_node_type
net‐
bios_scope
nis_domain_name
nis_server
non-
local_source_rout‐
ing
ntp_server
path_mtu_aging_time‐
out
path_mtu_plateau_ta‐
ble
per‐
form_mask_dis‐
cov‐
ery
per‐
form_router_dis‐
cov‐
ery
pol‐
icy_fil‐
ter
rebind‐
ing_time_value
renewal_time_value
resource_loca‐
tion_server
root_path
router
router_solic‐
i‐
ta‐
tion_address
static_routes
sub‐
net_mask
swap_server
tcp_default_time_to_live
tcp_keepalive_inter‐
val
time_off‐
set
time_server_(rfc_868)
trailer_encap‐
su‐
la‐
tion
x_win‐
dow_dis‐
play_man‐
ager
x_win‐
dows_font_server
The following are specific to the DHCP server:
nfs_mounted_file_sys‐
tems
svr4_printer_set‐
up
print‐
ers
RELATED INFORMATIONjoinc(8)
DARPA Internet Request For Comments RFC 1541, RFC 1542 delim off
client.pcy(4)