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Ted Lemon
1999-07-07 16:36:58 +00:00
parent ca4606b509
commit f8b6e76081
4 changed files with 877 additions and 85 deletions
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122
client/dhclient.cat8
View File

@@ -8,7 +8,9 @@ NNAAMMEE
dhclient - Dynamic Host Configuration Protocol Client dhclient - Dynamic Host Configuration Protocol Client
SSYYNNOOPPSSIISS SSYYNNOOPPSSIISS
ddhhcclliieenntt [ --pp _p_o_r_t ] [ --dd ] [ _i_f_0 [ _._._._i_f_N ] ] ddhhcclliieenntt [ --pp _p_o_r_t ] [ --dd ] [ --DD ] [ --qq ] [ --cc ] [ --llff
_l_e_a_s_e_-_f_i_l_e ] [ --ppff _p_i_d_-_f_i_l_e ] [ --ccff _c_o_n_f_i_g_-_f_i_l_e ] [ --ss
server ] [ _i_f_0 [ _._._._i_f_N ] ]
DDEESSCCRRIIPPTTIIOONN DDEESSCCRRIIPPTTIIOONN
The Internet Software Consortium DHCP Client, dhclient, The Internet Software Consortium DHCP Client, dhclient,
@@ -56,8 +58,6 @@ OOPPEERRAATTIIOONN
leases from the dhclient.leases file which have not yet leases from the dhclient.leases file which have not yet
expired are tested, and if they are determined to be expired are tested, and if they are determined to be
valid, they are used until either they expire or the DHCP valid, they are used until either they expire or the DHCP
server becomes available.
@@ -70,6 +70,8 @@ OOPPEERRAATTIIOONN
dhclient(8) dhclient(8) dhclient(8) dhclient(8)
server becomes available.
A mobile host which may sometimes need to access a network A mobile host which may sometimes need to access a network
on which no DHCP server exists may be preloaded with a on which no DHCP server exists may be preloaded with a
lease for a fixed address on that network. When all lease for a fixed address on that network. When all
@@ -88,22 +90,75 @@ CCOOMMMMAANNDD LLIINNEE
The names of the network interfaces that dhclient should The names of the network interfaces that dhclient should
attempt to configure may be specified on the command line. attempt to configure may be specified on the command line.
If no interface names are specified on the command line If no interface names are specified on the command line
dhclient will identify all network interfaces, elimininat<61> dhclient will normally identify all network interfaces,
ing non-broadcast interfaces if possible, and attempt to elimininating non-broadcast interfaces if possible, and
configure each interface. attempt to configure each interface.
If dhclient should listen and transmit on a port other It is also possible to specify interfaces by name in the
than the standard (port 68), the --pp flag may used. It ddhhcclliieenntt..ccoonnff((55)) file. If interfaces are specified in
should be followed by the udp port number that dhclient this way, then the client will only configure interfaces
that are either specified in the configuration file or on
the command line, and will ignore all other interfaces.
If the DHCP client should listen and transmit on a port
other than the standard (port 68), the --pp flag may used.
It should be followed by the udp port number that dhclient
should use. This is mostly useful for debugging purposes. should use. This is mostly useful for debugging purposes.
If a different port is specified for the client to listen
on and transmit on, the client will also use a different
destination port - one greater than the specified destina<6E>
tion port.
Dhclient will normally run in the foreground until it has The DHCP client normally transmits any protocol messages
configured an interface, and then will revert to running it sends before acquiring an IP address to,
in the background. To run force dhclient to always run as 255.255.255.255, the IP limited broadcast address. For
a foreground process, the --dd flag should be specified. debugging purposes, it may be useful to have the server
This is useful when running dhclient under a debugger, or transmit these messages to some other address. This can
when running it out of inittab on System V systems. be specified with the --ss flag, followed by the IP address
or domain name of the destination.
The DHCP client will normally run in the foreground until
it has configured an interface, and then will revert to
running in the background. To run force dhclient to
always run as a foreground process, the --dd flag should be
specified. This is useful when running the client under a
debugger, or when running it out of inittab on System V
systems.
2
dhclient(8) dhclient(8)
The client writes a temporary shell script whenever it
invokes dhclient-script. This script is normally deleted
after the client runs, but it can be helpful when debug<75>
ging the client script to see what the client wrote. The
client can be configured not to delete these scripts by
specifying the --DD flag.
The client normally prints a startup message and displays
the protocol sequence to the standard error descriptor
until it has acquired an address, and then only logs mes<65>
sages using the ssyysslloogg ((33)) facility. The --qq flag pre<72>
vents any messages other than errors from being printed to
the standard error descriptor.
The DHCP client normally gets its configuration informa<6D>
tion from //eettcc//ddhhcclliieenntt..ccoonnff,, its lease database from
//vvaarr//ddbb//ddhhcclliieenntt..lleeaasseess and stores its process ID in a
file called //vvaarr//rruunn//ddhhcclliieenntt..ppiidd.. To specify different
names and/or locations for these files, use the --ccff,, --llff
and --ppff flags, respectively, followed by the name of the
file. This can be particularly useful if, for example,
//vvaarr//ddbb or //vvaarr//rruunn has not yet been mounted when the DHCP
client is started.
CCOONNFFIIGGUURRAATTIIOONN CCOONNFFIIGGUURRAATTIIOONN
The syntax of the dhclient.conf(8) file is discussed The syntax of the dhclient.conf(8) file is discussed
@@ -124,18 +179,6 @@ AAUUTTHHOORR
Software Consortium, see hhttttpp::////wwwwww..vviixx..ccoomm//iisscc.. To learn Software Consortium, see hhttttpp::////wwwwww..vviixx..ccoomm//iisscc.. To learn
more about Vixie Enterprises, see hhttttpp::////wwwwww..vviixx..ccoomm.. more about Vixie Enterprises, see hhttttpp::////wwwwww..vviixx..ccoomm..
2
dhclient(8) dhclient(8)
This client was substantially modified and enhanced by This client was substantially modified and enhanced by
Elliot Poger for use on Linux while he was working on the Elliot Poger for use on Linux while he was working on the
MosquitoNet project at Stanford. MosquitoNet project at Stanford.
@@ -147,6 +190,18 @@ dhclient(8) dhclient(8)
server uses. Much system-specific configuration code was server uses. Much system-specific configuration code was
moved into a shell script so that as support for more moved into a shell script so that as support for more
operating systems is added, it will not be necessary to operating systems is added, it will not be necessary to
3
dhclient(8) dhclient(8)
port and maintain system-specific configuration code to port and maintain system-specific configuration code to
these operating systems - instead, the shell script can these operating systems - instead, the shell script can
invoke the native tools to accomplish the same purpose. invoke the native tools to accomplish the same purpose.
@@ -193,6 +248,17 @@ dhclient(8) dhclient(8)
3
4

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common/dhcp-contrib.cat5 Normal file
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@@ -0,0 +1,330 @@
dhcp-contrib(5) dhcp-contrib(5)
NNAAMMEE
Contributing to the Internet Software Consortium DHCP Dis<69>
tribution
EEXXHHOORRTTAATTIIOONN
The Internet Software Consortium DHCP Distribution has
historically been funded through the donation of various
charitable and non-charitable organizations, as well as by
individual contributions. To some degree, support for the
distribution has been done on a volunteer basis, but by
and large the reason that you have this distribution in
your hands right now is because people like you have pro<72>
vided funding for it.
We would like to encourage you to continue to provide such
support, or to begin providing it if you have not in the
past. You are in no way obliged to provide us with any
support at all, and this message is not intended to guilt-
trip you about providing support. If you choose not to
provide support, for whatever reason, you aren't going to
be treated differently on the mailing lists, and your
requests for features aren't going to be prioritized any
differently. If you want to be treated differently, you
can buy a formal support contract, of course, but this
document is about contributions, not support contracts.
FFRREEQQUUEENNTTLLYY AASSKKEEDD QQUUEESSTTIIOONNSS
Q: So if I won't be treated differently, why contribute?
A: The obvious answer is self-interest. If you con<6F>
tribute, it means that the author will have time to work
on stuff that's not of the utmost high priority. People
are constantly asking for things that we would really like
to provide, but for which we have no time. By contribut<75>
ing, you are literally giving us time to do these things.
The amount of time varies with the contribution, of
course, but if everybody contributes a little bit, it can
add up to a lot.
Q: But everybody isn't required to contribute. If I con<6F>
tribute and nobody else does, doesn't that make me kind of
a sucker?
A: Obviously, we don't think so, but think about this: if
you contribute, then we can point out to others that we've
received contributions, and this will make the idea of
contributing seem more legitimate to them, making it more
likely that they will contribute. So your contribution
has more value than just the money you provide - it also
helps us to raise funds from others.
Q: If I contribute, I want a say in what work gets done.
A: We do sell support contracts, and we will also do
1
dhcp-contrib(5) dhcp-contrib(5)
development work on specification if we feel it is rele<6C>
vant (although you won't get to own it). This can be
quite expensive, though - much more than even the maximum
we'd expect you to donate. So no, contributing doesn't
buy you a say in what work gets done.
Q: I work for a charity that feeds the homeless. Should
my charity contribute?
A: Absolutely not! The idea here is not to take food out
of the mouths of poor people. If donating to us would
mean that somebody in need that you could have helped will
go without help, keep the money. It's not worth it to us.
This goes for providing shelter, psychiatric aid, legal
assistance, and any other similar charity work.
Q: Cool! I work for a university, helping students who
are in need of an education, so we shouldn't contribute,
right?
A: No, that's not quite what we mean. Sure, if you work
for an organization that provides free education to needy
people, at whatever level, then we'd rather you did that
than support us. But if your university has a big budget
for running the computer center, can afford to plant nice
gardens and maintain nice lawns, and maybe has all its
dorms wired for ethernet, then even if you qualify as a
nonprofit under federal law (or the law in your own coun<75>
try) you should still contribute. DHCP is just as much a
part of your infrastructure as your campus wiring.
Q: This software came on a CD that I bought. Haven't I
already contributed?
A: If you're seeing this notice, and you didn't see a
notice saying that the people who sold you your CD con<6F>
tributed to us, then no, you haven't already contributed.
In general, we encourage people to include this software
on their distributions if they feel it would be useful,
and we do not require them to contribute in exchange for
that privilege.
Q: I've contributed to the development of this software by
submitting bug reports and patches. Why should I also
contribute money?
A: When you contributed these bug reports and patches, was
there zero effort involved on our part in integrating the
patches or figuring out what was wrong? Probably not.
Bug reports and patches can be extremely valuable, and we
can't say that in no event do they qualify you to get out
of contributing - after all, we're leaving that up to your
judgement anyway, aren't we? But unless your contribution
was pretty massive, and is actually in this distribution,
2
dhcp-contrib(5) dhcp-contrib(5)
we aren't likely to agree with you about this.
Q: Software should be free. You have no right to ask for
money to support this effort.
A: You are entitled to that opinion, but please don't
raise it on the mailing list, as it will tend to get peo<65>
ple excited. Please remember that while copying software
is generally a very cheap process, creating it is not.
The amount of work that's gone into this software package
is quite significant, and there's plenty more work to do.
If you happen to be in college, working toward your
degree, and have no social life (and yes, I've been there
and done that) then it can seem like there's no additional
cost to hacking on software - after all, it's fun, isn't
it? While this is true, it is also true that you're a lot
better off with this software than you would have been
with the software I wrote in college. Enough said?
Q: Can't I contribute work instead of software?
A: We'd like to encourage that to some extent, and are
indeed trying to bring some developers into the fold, but
you shouldn't expect that your willingness to do this
translates directly into an opportunity. For example, you
may want very much to work for [insert the name of your
favorite commercial Linux vendor here], but unless you
have the appropriate skills, they like you, they're will<6C>
ing to pay what you need, and they have work that's appro<72>
priate to your skills, you're not going to get hired
there.
Q: I don't contribute to the Free Software Foundation -
why do you rate?
A: You should contribute to the Free Software Foundation
too!
Q: I don't contribute to [insert name of your local food
bank here]. Why do you rate?
A: If you feel bad about not contributing to the local
food bank, this is a very easy problem to solve, and we
encourage you to do so.
Q: Once I've contributed once, am I done?
A: We'd like to encourage you to contribute once a year.
If you want, we can send you a reminder notice on the year
anniversary of your original contribution. If you don't
specifically ask for this, we won't force it on you. No
salesperson will call. No spam will be sent. We defi<66>
nitely won't try to convince you that it's been a year
since you last contributed when it hasn't been a year yet.
3
dhcp-contrib(5) dhcp-contrib(5)
Q: I don't have you in my budget this year.
A: Fine, put us in your budget for next year!
Q: It's really hard to do charitable contributions at my
organization.
A: We'd be happy to sell you a product instead. If you
choose to go down this route, what we'l sell you is a
license for some number of clients and a CD. Just let us
know how many DHCP clients you have, and we'll use the
following schedule to figure out how much to invoice you
(shipping is included on orders of $100 or more). Even if
you can do charitable contributions, you might want to use
this schedule as a guideline for figuring out how much to
donate. It is only a guideline, of course - if the
amounts listed feel like too much or too little to you, do
what seems appropriate.
$10k for businesses supporting >10k nodes
$5k for charities supporting >10k nodes
$2.5k for businesses supporting >1k nodes
$1k for charities supporting >1k nodes
$500 for businesses with >500 nodes
$250 for charities with >500 nodes
$200 for businesses with >150 nodes
$100 for charities with >150 nodes
$100 for businesses with <150 nodes
$50 for charities with <150 nodes
$25 for home use, client or server
$0.10 to $1 per client for businesses that are reselling the
client, depending on volume.
Q: Are you nuts? I live in [insert your country name
here] and the typical annual salary for a programmer is
less than what you're asking me to contribute!
A: We leave the choice of how much to contribute up to
you. Really. We aren't kidding.
Q: Can I contribute with my credit card?
A: Yes. The details haven't been ironed out at this
writing, but if you send mail to dhcp-contribu<62>
tions@isc.org, we'll work it out. By the time you read
this, we may have a web interface set up - if so, it will
be linked in at http://www.isc.org/dhcp-contrib.html.
SSEEEE AALLSSOO
dhcpd.conf(5), dhcpd.leases(5), dhclient.conf(5),
dhcpd(8), dhclient(8), RFC2132, RFC2131.
AAUUTTHHOORR
The Internet Software Consortium DHCP Distribution was
4
dhcp-contrib(5) dhcp-contrib(5)
written by Ted Lemon <mellon@isc.org> under a contract
with Vixie Labs. Funding for this project was provided
through the Internet Software Consortium. Information
about the Internet Software Consortium can be found at
hhttttpp::////wwwwww..iisscc..oorrgg//iisscc..
5

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@@ -0,0 +1,396 @@
dhcpd-options(5) dhcpd-options(5)
NNAAMMEE
dhcp-conditionals - ISC DHCP conditional evaluation
DDEESSCCRRIIPPTTIIOONN
The Internet Software Consortium DHCP client and server
both provide the ability to perform conditional behavior
depending on the contents of packets they receive. The
syntax for specifying this conditional behaviour is docu<63>
mented here.
RREEFFEERREENNCCEE:: CCOONNDDIITTIIOONNAALL BBEEHHAAVVIIOOUURR
Conditional behaviour is specified using the if statement
and the else or elsif statements. A conditional state<74>
ment can appear anywhere that a regular statement (e.g.,
an option statement) can appear, and can enclose one or
more such statements. A typical conditional statement in
a server might be:
if option dhcp-user-class = "accounting" {
max-lease-time 17600;
option domain-name "accounting.example.org";
option domain-name-servers ns1.accounting.example.org,
ns2.accounting.example.org;
} elsif option dhcp-user-class = "sales" {
max-lease-time 17600;
option domain-name "sales.example.org";
option domain-name-servers ns1.sales.example.org,
ns2.sales.example.org;
} elsif option dhcp-user-class = "engineering" {
max-lease-time 17600;
option domain-name "engineering.example.org";
option domain-name-servers ns1.engineering.example.org,
ns2.engineering.example.org;
} else {
max-lease-time 600;
option domain-name "misc.example.org";
option domain-name-servers ns1.misc.example.org,
ns2.misc.example.org;
}
On the client side, an example of conditional evaluation
might be:
# example.org filters DNS at its firewall, so we have to use their DNS
# servers when we connect to their network. If we are not at
# example.org, prefer our own DNS server.
if not option domain-name = "example.org" {
prepend domain-name-servers 127.0.0.1;
}
The iiff statement and the eellssiiff continuation statement both
take boolean expressions as their arguments. That is,
they take expressions that, when evaluated, produce a
boolean result. If the expression evaluates to true,
1
dhcpd-options(5) dhcpd-options(5)
then the statements enclosed in braces following the iiff
statement are executed, and all subsequent eellssiiff and eellssee
clauses are skipped. Otherwise, each subsequent eellssiiff
clause's expression is checked, until an elsif clause is
encountered whose test evaluates to true. If such a
clause is found, the statements in braces following it are
executed, and then any subsequent eellssiiff and eellssee clauses
are skipped. If all the iiff and eellssiiff clauses are checked
but none of their expressions evaluate true, then if there
is an eellssee clause, the statements enclosed in braces fol<6F>
lowing the eellssee are evaluated. Boolean expressions that
evaluate to null are treated as false in conditionals.
BBOOOOLLEEAANN EEXXPPRREESSSSIIOONNSS
The following is the current list of boolean expressions
that are supported by the DHCP distribution.
cchheecckk _c_l_a_s_s_-_n_a_m_e
The check operator returns a true value if the packet
being considered comes from a client that falls into
the specified class. _C_l_a_s_s_-_n_a_m_e must be a string that
corresponds to the name of a defined class. Classes
are only supported in the DHCP server.
_d_a_t_a_-_e_x_p_r_e_s_s_i_o_n_-_1 == _d_a_t_a_-_e_x_p_r_e_s_s_i_o_n_-_2
The == operator compares the values of two data expres<65>
sions, returning true if they are the same, false if
they are not. If either the left-hand side or the
right-hand side are null, the result is also null.
_b_o_o_l_e_a_n_-_e_x_p_r_e_s_s_i_o_n_-_1 aanndd _b_o_o_l_e_a_n_-_e_x_p_r_e_s_s_i_o_n_-_2
The aanndd operator evaluates to true if the boolean
expression on the left-hand side and the boolean
expression on the right-hand side both evaluate to
true. Otherwise, it evaluates to false. If either the
expression on the left-hand side or the expression on
the right-hand side are null, the result is null.
_b_o_o_l_e_a_n_-_e_x_p_r_e_s_s_i_o_n_-_1 oorr _b_o_o_l_e_a_n_-_e_x_p_r_e_s_s_i_o_n_-_2
The oorr operator evaluates to true if either the boolean
expression on the left-hand side or the boolean expres<65>
sion on the right-hand side evaluate to true. Other<65>
wise, it evaluates to false. If either the expression
on the left-hand side or the expression on the right-
hand side are null, the result is null.
nnoott _b_o_o_l_e_a_n_-_e_x_p_r_e_s_s_i_o_n
The nnoott operator evaluates to true if _b_o_o_l_e_a_n_-_e_x_p_r_e_s_<08>
_s_i_o_n evaluates to false, and returns false if _b_o_o_l_e_a_n_-
2
dhcpd-options(5) dhcpd-options(5)
_e_x_p_r_e_s_s_i_o_n evaluates to true. If _b_o_o_l_e_a_n_-_e_x_p_r_e_s_s_i_o_n
evaluates to null, the result is also null.
eexxiissttss _o_p_t_i_o_n_-_n_a_m_e
The eexxiissttss expression returns true if the specified
option exists in the incoming DHCP packet being pro<72>
cessed.
kknnoowwnn
The kknnoowwnn expression returns true if the client whose
request is currently being processed is known - that
is, if there's a host declaration for it.
DDAATTAA EEXXPPRREESSSSIIOONNSS
Several of the boolean expressions above depend on the
results of evaluating data expressions. A list of these
expressions is provided here.
ssuubbssttrriinngg ((_d_a_t_a_-_e_x_p_r,, _o_f_f_s_e_t,, _l_e_n_g_t_h))
The ssuubbssttrriinngg operator evaluates the data expression
and returns the substring of the result of that evalua<75>
tion that starts _o_f_f_s_e_t bytes from the beginning, con<6F>
tinuing for _l_e_n_g_t_h bytes. _O_f_f_s_e_t and _l_e_n_g_t_h are both
numeric expressions. If _d_a_t_a_-_e_x_p_r, _o_f_f_s_e_t or _l_e_n_g_t_h
evaluate to null, then the result is also null. If
_o_f_f_s_e_t is greater than or equal to the length of the
evaluated data, then a zero-length data string is
returned. If _l_e_n_g_t_h _i_s _g_r_e_a_t_e_r _t_h_e_n _t_h_e _r_e_m_a_i_n_i_n_g
_l_e_n_g_t_h _o_f _t_h_e _e_v_a_l_u_a_t_e_d _d_a_t_a _a_f_t_e_r _o_f_f_s_e_t, then a data
string containing all data from _o_f_f_s_e_t to the end of
the evaluated data is returned.
ssuuffffiixx ((_d_a_t_a_-_e_x_p_r,, _l_e_n_g_t_h))
The ssuuffffiixx operator evaluates _d_a_t_a_-_e_x_p_r and returns the
last _l_e_n_g_t_h bytes of the result of that evaluation.
_L_e_n_g_t_h is a numeric expression. If _d_a_t_a_-_e_x_p_r or _l_e_n_g_t_h
evaluate to null, then the result is also null. If
_s_u_f_f_i_x evaluates to a number greater than the length of
the evaluated data, then the evaluated data is
returned.
ooppttiioonn _o_p_t_i_o_n_-_n_a_m_e
The ooppttiioonn operator returns the contents of the speci<63>
fied option in the packet to which the server is
responding.
hhaarrddwwaarree
The hhaarrddwwaarree operator returns a data string whose first
element is the _h_t_y_p_e field of the packet being
3
dhcpd-options(5) dhcpd-options(5)
considered, and whose subsequent elements are first
_h_l_e_n bytes of the _c_h_a_d_d_r field of the packet, as speci<63>
fied in RRFFCC 22113311 . If there is no packet, or if the
_h_l_e_n field is invalid, then the result is null.
ppaacckkeett ((_o_f_f_s_e_t,, _l_e_n_g_t_h))
The ppaacckkeett operator returns the specified portion of
the packet being considered, or null in contexts where
no packet is being considered. _O_f_f_s_e_t and _l_e_n_g_t_h are
applied to the contents packet as in the ssuubbssttrriinngg
operator.
_s_t_r_i_n_g
A string, enclosed in quotes, may be specified as a
data expression, and returns the text between the
quotes, encoded in ASCII.
_c_o_l_o_n_-_s_e_p_e_r_a_t_e_d _h_e_x_a_d_e_c_i_m_a_l _l_i_s_t
A list of hexadecimal octet values, seperated by
colons, may be specified as a data expression.
ccoonnccaatt ((_d_a_t_a_-_e_x_p_r_1,, _d_a_t_a_-_e_x_p_r_2))
The two expressions are evaluated, and the result of
concatenating the results of the two evaluations is
returned. If either subexpression evaluates to null,
then the result is the value of the other expression.
If both expressions evaluate to null, then the result
is null.
rreevveerrssee ((_n_u_m_e_r_i_c_-_e_x_p_r_1,, _d_a_t_a_-_e_x_p_r_2))
The two expressions are evaluated, and then the result
of evaluating the data expression is reversed in place,
using hunks of the size specified in the numeric
expression. For example, if the numeric expression
evaluates to four, and the data expression evaluates to
twelve bytes of data, then the reverse expression will
evaluate to twelve bytes of data, consisting of the
last four bytes of the the input data, followed by the
middle four bytes, followed by the first four bytes.
lleeaasseedd--aaddddrreessss
In any context where the client whose request is being
processed has been assigned an IP address, this data
expression returns that IP address.
bbiinnaarryy--ttoo--aasscciiii ((_n_u_m_e_r_i_c_-_e_x_p_r_1,, _n_u_m_e_r_i_c_-_e_x_p_r_2,, _d_a_t_a_-_e_x_p_r_1,,
_d_a_t_a_-_e_x_p_r_2))
Converts the result of evaluating data-expr2 into a
text string containing one number for each element of
the result of evaluating data-expr2. Each number is
4
dhcpd-options(5) dhcpd-options(5)
seperated from the other by the result of evaluating
data-expr1. The result of evaluating numeric-expr1
specifies the base (2 through 16) into which the num<75>
bers should be converted. The result of evaluating
numeric-expr2 specifies the width in bits of each num<75>
ber, which may be either 8, 16 or 32.
As an example of the preceding three types of expres<65>
sions, to produce the name of a PTR record for the IP
address being assigned to a client, one could write the
following expression:
concat (binary-to-ascii (10, 8, ".",
reverse (1, leased-address)),
".in-addr.arpa.");
eennccooddee--iinntt ((_n_u_m_e_r_i_c_-_e_x_p_r,, _w_i_d_t_h))
Numeric-expr is evaluated and encoded as a data string
of the specified width, in network byte order (most
significant byte first). If the numeric expression
evaluates to the null value, the result is also null.
NNUUMMEERRIICC EEXXPPRREESSSSIIOONNSS
Numeric expressions are expressions that evaluate to an
integer. In general, the maximum size of such an integer
should not be assumed to be representable in fewer than 32
bits, but the precision of such integers may be more than
32 bits.
eexxttrraacctt--iinntt ((_d_a_t_a_-_e_x_p_r,, _w_i_d_t_h))
The eexxttrraacctt--iinntt operator extracts an integer value in
network byte order from the result of evaluating the
specified data expression. Width is the width in bits
of the integer to extract. Currently, the only sup<75>
ported widths are 8, 16 and 32. If the evaluation of
the data expression doesn't provide sufficient bits to
extract an integer of the specified size, the null
value is returned.
_n_u_m_b_e_r
Any number between zero and the maximum representable
size may be specified as a numeric expression.
SSEEEE AALLSSOO
dhcpd.conf(5), dhcpd.leases(5), dhclient.conf(5), dhcp-
eval(5), dhcpd(8), dhclient(8), RFC2132, RFC2131.
AAUUTTHHOORR
The Internet Software Consortium DHCP Distribution was
written by Ted Lemon <mellon@isc.org> under a contract
5
dhcpd-options(5) dhcpd-options(5)
with Vixie Labs. Funding for this project was provided
through the Internet Software Consortium. Information
about the Internet Software Consortium can be found at
hhttttpp::////wwwwww..iisscc..oorrgg//iisscc..
6

114
server/dhcpd.conf.cat5
View File

@@ -552,7 +552,7 @@ dhcpd.conf(5) dhcpd.conf(5)
you can write a class declaration as follows: you can write a class declaration as follows:
class "customer" { class "customer" {
match if exists agent.circuit-id; match if exists agent.circuit-id;
spawn with agent.circuit-id; spawn with option agent.circuit-id;
lease limit 4; lease limit 4;
} }
@@ -1179,7 +1179,7 @@ dhcpd.conf(5) dhcpd.conf(5)
set in any scope, and will affect all clients covered by set in any scope, and will affect all clients covered by
that scope. that scope.
TThhee _u_s_e_-_l_e_a_s_e_-_a_d_d_r_-_f_o_r_-_d_e_f_a_u_l_t_-_r_o_u_t_e ssttaatteemmeenntt TThhee _a_l_w_a_y_s_-_b_r_o_a_d_c_a_s_t ssttaatteemmeenntt
@@ -1192,6 +1192,38 @@ dhcpd.conf(5) dhcpd.conf(5)
dhcpd.conf(5) dhcpd.conf(5) dhcpd.conf(5) dhcpd.conf(5)
aallwwaayyss--bbrrooaaddccaasstt _f_l_a_g;;
The DHCP and BOOTP protocols both require DHCP and BOOTP
clients to set the broadcast bit in the flags field of the
BOOTP message header. Unfortunately, some DHCP and BOOTP
clients do not do this, and therefore may not receive
responses from the DHCP server. The DHCP server can be
made to always broadcast its responses to clients by set<65>
ting this flag to 'on' for the relevant scope. To avoid
creating excess broadcast traffic on your network, we rec<65>
ommend that you restrict the use of this option to as few
clients as possible. For example, the Microsoft DHCP
client is known not to have this problem, as are the Open<65>
Transport and ISC DHCP clients.
TThhee _o_n_e_-_l_e_a_s_e_-_p_e_r_-_c_l_i_e_n_t ssttaatteemmeenntt
oonnee--lleeaassee--ppeerr--cclliieenntt _f_l_a_g;;
If this flag is enabled, whenever a client sends a DHCPRE<52>
QUEST for a particular lease, the server will automati<74>
cally free any other leases the client holds. This pre<72>
sumes that when the client sends a DHCPREQUEST, it has
forgotten any lease not mentioned in the DHCPREQUEST -
i.e., the client has only a single network interface _a_n_d
it does not remember leases it's holding on networks to
which it is not currently attached. Neither of these
assumptions are guaranteed or provable, so we urge caution
in the use of this statement.
TThhee _u_s_e_-_l_e_a_s_e_-_a_d_d_r_-_f_o_r_-_d_e_f_a_u_l_t_-_r_o_u_t_e ssttaatteemmeenntt
uussee--lleeaassee--aaddddrr--ffoorr--ddeeffaauulltt--rroouuttee _f_l_a_g;; uussee--lleeaassee--aaddddrr--ffoorr--ddeeffaauulltt--rroouuttee _f_l_a_g;;
If the _u_s_e_-_l_e_a_s_e_-_a_d_d_r_-_f_o_r_-_d_e_f_a_u_l_t_-_r_o_u_t_e parameter is true If the _u_s_e_-_l_e_a_s_e_-_a_d_d_r_-_f_o_r_-_d_e_f_a_u_l_t_-_r_o_u_t_e parameter is true
@@ -1214,6 +1246,18 @@ dhcpd.conf(5) dhcpd.conf(5)
The use of the server-identifier statement is not recom<6F> The use of the server-identifier statement is not recom<6F>
mended - the only reason to use it is to force a value mended - the only reason to use it is to force a value
19
dhcpd.conf(5) dhcpd.conf(5)
other than the default value to be sent on occasions where other than the default value to be sent on occasions where
the default value would be incorrect. The default value the default value would be incorrect. The default value
is the first IP address associated with the physical net<65> is the first IP address associated with the physical net<65>
@@ -1246,18 +1290,6 @@ VVEENNDDOORR EENNCCAAPPSSUULLAATTEEDD OOPPTTIIOONNSS
You can send this option to clients in one of two ways - You can send this option to clients in one of two ways -
either define the data directly, using a text string or a either define the data directly, using a text string or a
colon-seperated list of hexadecimal values, or define an colon-seperated list of hexadecimal values, or define an
19
dhcpd.conf(5) dhcpd.conf(5)
option space, define some options in that option space, option space, define some options in that option space,
provide values for them, and specify that that option provide values for them, and specify that that option
space should be used to generate the vveennddoorr--eennccaappssuullaatteedd-- space should be used to generate the vveennddoorr--eennccaappssuullaatteedd--
@@ -1281,6 +1313,17 @@ dhcpd.conf(5) dhcpd.conf(5)
option SUNW.server-name code 3 = text; option SUNW.server-name code 3 = text;
option SUNW.root-path code 4 = text; option SUNW.root-path code 4 = text;
20
dhcpd.conf(5) dhcpd.conf(5)
Once you have defined an option space and some options, Once you have defined an option space and some options,
you can set up scopes that define values for those you can set up scopes that define values for those
options, and you can say when to use them. For example, options, and you can say when to use them. For example,
@@ -1312,18 +1355,6 @@ dhcpd.conf(5) dhcpd.conf(5)
to a particular class in the local scope. The vveennddoorr-- to a particular class in the local scope. The vveennddoorr--
ooppttiioonn--ssppaaccee declaration indicates that in that scope, the ooppttiioonn--ssppaaccee declaration indicates that in that scope, the
vveennddoorr--eennccaappssuullaatteedd--ooppttiioonnss option should be constructed vveennddoorr--eennccaappssuullaatteedd--ooppttiioonnss option should be constructed
20
dhcpd.conf(5) dhcpd.conf(5)
using the values of all the options in the SUNW option using the values of all the options in the SUNW option
space. space.
@@ -1350,37 +1381,6 @@ AAUUTTHHOORR
21 21