Flense dhclient.conf.5 down to useful information. Move

description of "lease {}" format to dhlcient.leases.5.
Neither implement standards so coalesce STANDARDS sections
into dhclient.8. AUTHOR and HISTORY sections not normally
used for .conf man pages so drop them. Many tweaks.

Language/formatting suggestions, stamp of approved by jmc@.

3 files changed, 246 insertions, 447 deletions

diff --git a/sbin/dhclient/dhclient.8 b/sbin/dhclient/dhclient.8
index 0c4a8296da0..e95b9bb33d0 100644
--- a/sbin/dhclient/dhclient.8
+++ b/sbin/dhclient/dhclient.8
@@ -1,4 +1,4 @@
-.\" $OpenBSD: dhclient.8,v 1.33 2017/09/22 14:04:13 krw Exp $
+.\" $OpenBSD: dhclient.8,v 1.34 2017/10/20 13:04:50 krw Exp $
 .\"
 .\" Copyright (c) 1997 The Internet Software Consortium.
 .\" All rights reserved.
@@ -35,7 +35,7 @@
 .\" Enterprises.  To learn more about the Internet Software Consortium,
 .\" see ``http://www.isc.org/isc''.  To learn more about Vixie
 .\" Enterprises, see ``http://www.vix.com''.
-.Dd $Mdocdate: September 22 2017 $
+.Dd $Mdocdate: October 20 2017 $
 .Dt DHCLIENT 8
 .Os
 .Sh NAME
@@ -118,7 +118,7 @@ will be the lease offered by the DHCP server;
 will be the modified lease bound to the interface.
 .It Fl l Ar file
 Specify an alternate location to
-.Pa /var/db/dhclient.leases. Ns Aq Ar IFNAME
+.Pa /var/db/dhclient.leases . Ns Aq Ar IFNAME
 for the leases file.
 .It Fl q
 Forces
@@ -198,7 +198,7 @@ In order to keep track of leases across system reboots and server
 restarts,
 .Nm
 keeps a list of leases it has been assigned in the
-.Pa /var/db/dhclient.leases. Ns Aq Ar IFNAME
+.Pa /var/db/dhclient.leases . Ns Aq Ar IFNAME
 file.
 .Ar IFNAME
 represents the network interface of the DHCP client
@@ -216,7 +216,7 @@ Old leases are kept around in case the DHCP server is unavailable when
 is first invoked (generally during the initial system boot
 process).
 In that event, old leases from the
-.Pa dhclient.leases. Ns Aq Ar IFNAME
+.Pa dhclient.leases . Ns Aq Ar IFNAME
 file which have not yet expired are tested, and if they are determined to
 be valid, they are used until either they expire or the DHCP server
 becomes available.
@@ -251,7 +251,7 @@ and obtaining a new lease.
 DHCP client configuration file
 .It Pa /etc/hostname.XXX
 interface-specific configuration files
-.It Pa /var/db/dhclient.leases. Ns Aq Ar IFNAME
+.It Pa /var/db/dhclient.leases . Ns Aq Ar IFNAME
 database of acquired leases
 .El
 .Sh SEE ALSO
@@ -299,6 +299,15 @@ database of acquired leases
 .%R RFC 3442
 .%T The Classless Static Route Option for Dynamic Host Configuration Protocol (DHCP) version 4
 .Re
+.Pp
+.Rs
+.%A N. Swamy
+.%A G. Halwasia
+.%A P. Jhingram
+.%D January 2013
+.%R RFC 6842
+.%T Client Identifier Option in DHCP Server Replies
+.Re
 .Sh AUTHORS
 .An -nosplit
 .Nm
diff --git a/sbin/dhclient/dhclient.conf.5 b/sbin/dhclient/dhclient.conf.5
index 20ffe8f9d34..b68babbadda 100644
--- a/sbin/dhclient/dhclient.conf.5
+++ b/sbin/dhclient/dhclient.conf.5
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: dhclient.conf.5,v 1.35 2017/07/31 18:56:21 anton Exp $
+.\"	$OpenBSD: dhclient.conf.5,v 1.36 2017/10/20 13:04:50 krw Exp $
 .\"
 .\" Copyright (c) 1997 The Internet Software Consortium.
 .\" All rights reserved.
@@ -36,7 +36,7 @@
 .\" see ``http://www.isc.org/isc''.  To learn more about Vixie
 .\" Enterprises, see ``http://www.vix.com''.
 .\"
-.Dd $Mdocdate: July 31 2017 $
+.Dd $Mdocdate: October 20 2017 $
 .Dt DHCLIENT.CONF 5
 .Os
 .Sh NAME
@@ -46,442 +46,191 @@
 .Nm
 is the configuration file for
 .Xr dhclient 8 .
-.Pp
-The
-.Nm
-file is a free-form ASCII text file that may contain extra tabs and newlines for
-formatting purposes.
+It is a free-form ASCII text file made up of declarations, extra
+tabs and newlines for formatting purposes and comments.
 Keywords in the file are case-insensitive.
-Comments may be placed anywhere within the file (except within quotes).
 Comments begin with the
 .Sq #
 character and extend to the end of the current line.
-.Pp
-The
-.Nm
-file can be used to configure the behaviour of the client in a wide variety
-of ways: protocol timing, information requested from the server, information
-required of the server, defaults to use if the server does not provide
-certain information, values with which to override information provided by
-the server, or values to prepend or append to information provided by the
-server.
-The configuration file can also be preinitialized with addresses to
-use on networks that don't have DHCP servers.
-.Sh PROTOCOL TIMING
-The timing behaviour of the client need not be configured by the user.
-If no timing configuration is provided by the user, a fairly
-reasonable timing behaviour will be used by default \- one which
-results in fairly timely updates without placing an inordinate load on
-the server.
-.Pp
-The following statements can be used to adjust the timing behaviour of
-the DHCP client if required, however:
+.Sh PROTOCOL TIMING DECLARATIONS
 .Bl -tag -width Ds
-.It Ic timeout Ar time ;
-The
-.Ic timeout
-statement determines the amount of time that must pass between the
-time that the client begins to try to determine its address and the
-time that it decides that it's not going to be able to contact a server.
-After the timeout has passed, if there are any static leases defined in the
-configuration file, or any leases remaining in the lease database that
-have not yet expired, the client will loop through these leases
-attempting to validate them, and if it finds one that appears to be
-valid, it will use that lease's address.
-If there are no valid static leases or unexpired leases in the lease database,
-the client will restart the protocol after the defined retry interval.
-.Pp
-By default,
-.Ic timeout
-is set to thirty seconds.
-.It Ic retry Ar time ;
-The
-.Ic retry
-statement determines the time that must pass after the client has
-determined that there is no DHCP server present before it tries again
-to contact a DHCP server.
-.Pp
-By default,
-.Ic retry
-is set to one second.
-.It Ic select-timeout Ar time ;
-It is possible (some might say desirable) for there to be more than
-one DHCP server serving any given network.
-In this case, it is possible that a client may be sent more than one offer
-in response to its initial lease discovery message.
-It may be that one of these offers is preferable to the other
-(e.g., one offer may have the address the client previously used,
-and the other may not).
-.Pp
-The
-.Ic select-timeout
-is the time after the client sends its first lease discovery request
-at which it stops waiting for offers from servers, assuming that it
-has received at least one such offer.
-If no offers have been received by the time the
-.Ic select-timeout
-has expired, the client will accept the first offer that arrives.
-.Pp
-By default,
+.It Ic backoff-cutoff Ar seconds ;
+Sets the maximum number of seconds to
+wait before retransmitting a packet.
+The default is 10 seconds.
+.It Ic initial-interval Ar seconds ;
+Sets the number of seconds between the first packet transmission
+and the first retransmission of the packet.
+The default is 1 second.
+.It Ic link-timeout Ar seconds ;
+Sets the number of seconds
+to wait for interface link before going into the background as a daemon.
+The default is 10 seconds.
+.It Ic reboot Ar seconds ;
+Sets the number of seconds to wait
+before giving up on reacquiring the previous lease, and how long
+to attempt unicast renewal requests before falling back to broadcast
+renewal requests.
+The default is 1 second.
+.It Ic retry Ar seconds ;
+Sets the number of seconds to wait before starting a new attempt to
+obtain a lease.
+The default is 1 second.
+.It Ic select-timeout Ar seconds ;
+Sets the number of seconds to wait for additional leases after the
+first lease arrives.
+After
 .Ic select-timeout
-is set to zero seconds
-i.e. the client will immediately take the first offer it sees.
-.It Ic reboot Ar time ;
-When the client is restarted, it first tries to reacquire the last
-address it had.
-This is called the INIT-REBOOT state.
-If it is still attached to the same network it was attached to when it last
-ran, this is the quickest way to get started.
-The
-.Ic reboot
-statement sets the time that must elapse after the client first tries
-to reacquire its old address before it gives up and tries to discover
-a new address.
-.Pp
-The value of
-.Ic reboot
-is also used to control how long a client will attempt unicast renewal
-requests before falling back to using broadcast requests.
-.Pp
-By default,
-.Ic reboot
-is set to one second.
-.It Ic backoff-cutoff Ar time ;
-The client uses an exponential backoff algorithm with some randomness,
-so that if many clients try to configure themselves at the same time,
-they will not make their requests in lockstep.
-The
-.Ic backoff-cutoff
-statement determines the maximum amount of time that the client is
-allowed to back off.
-.Pp
-By default
-.Ic backoff-cutoff
-is set to ten seconds.
-.It Ic initial-interval Ar time ;
-The
-.Ic initial-interval
-statement sets the amount of time between the first attempt to reach a
-server and the second attempt to reach a server.
-Each time a message is sent, the interval between messages is incremented by
-twice the current interval multiplied by a random number between zero and one.
-If it is greater than the backoff-cutoff amount, it is set to that
-amount.
-.Pp
-By default
-.Ic initial-interval
-is set to one second.
-.It Ic link-timeout Ar time ;
-The
-.Ic link-timeout
-statement sets the amount of time to wait for an interface link before timing
-out.
-The value zero requests that
-dhclient not wait for a link state change before timing out.
-.Pp
-By default
-.Ic link-timeout
-is set to ten seconds.
+seconds the best lease received will be selected.
+The default is 0 seconds, i.e. immediately use
+the first acceptable lease received.
+.It Ic timeout Ar seconds ;
+Sets the number of seconds to wait for a lease.
+If no lease is received
+the first valid lease in
+.Nm
+or in
+.Xr dhclient.leases 5
+will be used.
+The default is 30 seonds.
 .El
-.Sh LEASE REQUIREMENTS AND REQUESTS
-The DHCP protocol allows the client to request that the server send it
-specific information, and not send it other information that it is not
-prepared to accept.
-The protocol also allows the client to reject offers from servers if they
-don't contain information the client needs, or if the information provided
-is not satisfactory.
-.Pp
-There is a variety of data contained in offers that DHCP servers send
-to DHCP clients.
-The data that can be specifically requested is what are called
-.Em DHCP Options .
-DHCP Options are defined in
-.Xr dhcp-options 5 .
+.Sh DHCP OPTION DECLARATIONS
 .Bl -tag -width Ds
+.It Ic append Ar option option-value ;
+Append
+.Ar option-value
+to the value of
+.Ar option
+in the lease.
+Each
+.Ic append
+for
+.Ar option
+overrides any previous
+.Ic append ,
+.Ic default ,
+.Ic prepend
+or
+.Ic supersede
+for
+.Ar option .
+.It Ic default Ar option option-value ;
+If no value for
+.Ar option
+is present in the lease use
+.Ar option-value .
+Each
+.Ic default
+for
+.Ar option
+overrides any previous
+.Ic append ,
+.Ic default ,
+.Ic prepend
+or
+.Ic supersede
+for
+.Ar option .
 .It Ic ignore Op Ar option , ... ;
-The
-.Ic ignore
-statement causes the client to discard values provided by the server for
-the specified options.
-Only option names should be specified in the ignore statement \- not
-option values.
-Only the last
-.Ic ignore
-statement has any effect, overriding any previous
+Discard values provided for the listed options.
+Each
 .Ic ignore
-statement.
+overrides any previous one.
+.It Ic prepend Ar option option-value ;
+Prepend
+.Ar option-value
+to the value of
+.Ar option
+in the lease.
+Each
+.Ic prepend
+for
+.Ar option
+overrides any previous
+.Ic append ,
+.Ic default ,
+.Ic prepend
+or
+.Ic supersede
+for
+.Ar option .
 .It Ic request Op Ar option , ... ;
-The
-.Ic request
-statement causes the client to request that any server responding to the
-client send the client its values for the specified options.
-Only option names should be specified in the request statement \- not
-option values.
-Only the last
-.Ic request
-statement has any effect, overriding any previous
+Ask that any lease contain values
+for the listed options.
+Each
 .Ic request
-statement.
-.It Ic require Op Ar option , ... ;
-The
-.Ic require
-statement lists options that must be sent in order for an offer to be accepted.
-Offers that do not contain all the listed options will be ignored.
-Only option names should be specified in the require statement \- not
-option values.
-Only the last
-.Ic require
-statement has any effect, overriding any previous
-.Ic require
-statement.
+overrides any previous one.
+The default is to request the options
+bootfile-name
+broadcast-address,
+classless-static-routes,
+host-name,
+domain-name,
+domain-name-servers,
+domain-search,
+routers,
+subnet-mask,
+tftp-server
+and
+time-offset.
 .It Ic send Ar option option-value ;
-The
-.Ic send
-statement causes the client to send the specified option and value
-to the server.
-Options that are always sent in the DHCP protocol should not be specified
-here.
-One use for this statement is to send information to the server
-that will allow it to differentiate between this client and other
-clients or kinds of clients.
-.El
-.Sh OPTION MODIFIERS
-Options in the lease can be modified before being accepted.
-.Pp
-Several option modifiers are available.
-.Bl -tag -width Ds
-.It Ic default Ar option option-value ;
-Use
+Include
 .Ar option-value
-for the given
-.Ar option ,
-if no value is supplied by the server.
+in requests for a lease.
+To include multiple options in requests,
+.Ic send
+can be used multiple times.
 .It Ic supersede Ar option option-value ;
 Use
 .Ar option-value
 for the given
-.Ar option ,
-regardless of the value supplied by the server.
-.It Ic prepend Ar option option-value ;
-Use
-.Ar option-value
-for the given
-.Ar option ,
-and then use the value supplied by the server.
+.Ar option
+regardless of the value in the lease.
+Each
+.Ic supersede
+for
+.Ar option
+overrides any previous
+.Ic append ,
+.Ic default ,
 .Ic prepend
-can only be used for options which allow more than one value to be given.
-The restriction is not enforced \- if violated, the results are unpredictable.
-.It Ic append Ar option option-value ;
-Use
-.Ar option-value
-for the given
-.Ar option ,
-after first using the value supplied by the server.
-.Ic append
-can only be used for options which allow more than one value to be given.
-The restriction is not enforced \- if violated, the results are unpredictable.
-.El
-.Sh LEASE DECLARATIONS
-The lease declaration:
-.Pp
-.D1 Ic lease No { Ar lease-declaration ; ... ; No }
-.Pp
-The DHCP client may decide after some period of time (see
-.Sx PROTOCOL TIMING )
-that it is not going to succeed in contacting a server.
-At that time, it consults its own database of old leases and tests each one
-that has not yet timed out by pinging the listed router for that lease to
-see if that lease could work.
-It is possible to define one or more
-.Em fixed
-leases in the client configuration file for networks where there is no DHCP
-or BOOTP service, so that the client can still automatically configure its
-address.
-This is done with the
-.Ic lease
-statement.
-.Pp
-NOTE: the lease statement is also used in the
-.Pa /var/db/dhclient.leases. Ns Aq Ar IFNAME
-file in order to record leases that have been received from DHCP servers.
-Some of the syntax for leases as described below is only needed in the
-.Pa /var/db/dhclient.leases. Ns Aq Ar IFNAME
-file.
-Such syntax is documented here for completeness.
-.Pp
-A lease statement consists of the lease keyword, followed by a left
-curly brace, followed by one or more lease declaration statements,
-followed by a right curly brace.
-The following lease declarations are possible:
-.Pp
-.Bl -tag -width Ds -compact
-.It Ic bootp ;
-The
-.Ic bootp
-statement is used to indicate that the lease was acquired using the
-BOOTP protocol rather than the DHCP protocol.
-It is never necessary to specify this in the client configuration file.
-The client uses this syntax in its lease database file.
-.Pp
-.It Ic interface Qq Ar string ;
-The
-.Ic interface
-lease statement is used to indicate the interface on which the lease is valid.
-If set, this lease will only be tried on a particular interface.
-When the client receives a lease from a server, it always records the
-interface number on which it received that lease.
-If predefined leases are specified in the
-.Nm
-file, the interface should also be specified, although this is not required.
-.Pp
-.It Ic fixed-address Ar ip-address ;
-The
-.Ic fixed-address
-statement is used to set the IP address of a particular lease.
-This is required for all lease statements.
-The IP address must be specified as a dotted quad (e.g., 12.34.56.78).
-.Pp
-.It Ic filename Qq Ar string ;
-The
-.Ic filename
-statement specifies the name of the boot filename to use.
-This is not used by the standard client, but is included for completeness.
-.Pp
-.It Ic server-name Qq Ar string ;
-The
-.Ic server-name
-statement specifies the name of the boot server name to use.
-This is not used by the standard client, but is included for completeness.
-.Pp
-.It Ic option Ar option option-value ;
-The
-.Ic option
-statement is used to specify the value of an option supplied by the server,
-or, in the case of predefined leases declared in
-.Nm dhclient.conf ,
-the value that the user wishes the client to use if the
-predefined lease is used.
-.Pp
-.It Ic renew Ar date ;
-.It Ic rebind Ar date ;
-.It Ic expire Ar date ;
-The
-.Ic renew
-statement defines the time at which the DHCP client should begin trying to
-contact its server to renew a lease that it is using.
-The
-.Ic rebind
-statement defines the time at which the DHCP client should begin to try to
-contact
-.Em any
-DHCP server in order to renew its lease.
-The
-.Ic expire
-statement defines the time at which the DHCP client must stop using a lease
-if it has not been able to contact a server in order to renew it.
+or
+.Ic supersede
+for
+.Ar option .
 .El
-.Pp
-These declarations are automatically set in leases acquired by the
-DHCP client, but must also be configured in predefined leases \- a
-predefined lease whose expiry time has passed will not be used by the
-DHCP client.
-.Pp
-Dates are specified as follows:
-.Pp
-.D1 <weekday> <year>/<month>/<day> <hour>:<minute>:<second>
-.Pp
-The weekday is present to make it easy for a human to tell when a
-lease expires \- it's specified as a number from zero to six, with zero
-being Sunday.
-When declaring a predefined lease, it can always be specified as zero.
-The year is specified with the century, so it should generally be four
-digits except for really long leases.
-The month is specified as a number starting with 1 for January.
-The day of the month is likewise specified starting with 1.
-The hour is a number between 0 and 23,
-the minute a number between 0 and 59,
-and the second also a number between 0 and 59.
 .Sh OTHER DECLARATIONS
 .Bl -tag -width Ds
+.It Ic interface Qo Ar name Qc No { Ar declaration ; ... ; No }
+Apply any
+.Ar declaration
+only to the named interface.
+.Ar interface
+declarations cannot be nested and cannot contain
+.Ar lease
+declarations.
+.It Ic lease No { Ar declaration ; ... ; No }
+Define a lease that can be used when no lease is obtained from a server.
+See
+.Xr dhclient.leases 5
+for the complete description of the
+.Ic lease
+format.
 .It Ic reject Ar ip-address ;
-The
+Discard leases from the specified address.
+If more than one
 .Ic reject
-statement causes the DHCP client to reject offers from servers who use
-the specified address as a server identifier.
-This can be used to avoid being configured by rogue or misconfigured DHCP
-servers, although it should be a last resort \- better to track down
-the bad DHCP server and fix it.
-.It Ic interface Qo Ar name Qc No { Ar declaration ; ... ; No }
-A client with more than one network interface may require different
-behaviour depending on which interface is being configured.
-All timing parameters and declarations other than lease
-declarations can be enclosed in an interface declaration, and those
-parameters will then be used only for the interface that matches the
-specified name.
-Interfaces for which there is no interface declaration will use the
-parameters declared outside of any interface declaration,
-or the default settings.
+is present all leases from any of the
+addresses will be discarded.
+.It Ic require Op Ar option , ... ;
+Discard leases that do not contain all the listed options.
+Each
+.Ic require
+overrides any previous one.
 .El
-.Sh EXAMPLES
-The following configuration file is used on a laptop
-which has one interface, ep0 (a 3Com 3C589C).
-Booting intervals have been shortened somewhat from the default, because
-the client is known to spend most of its time on networks with little DHCP
-activity.
-The laptop does roam to multiple networks.
-.Bd -literal -offset indent
-timeout 60;
-retry 60;
-reboot 10;
-select-timeout 5;
-initial-interval 2;
-reject 192.33.137.209;
-
-interface "ep0" {
-    send host-name "andare.fugue.com";
-    send dhcp-client-identifier 1:0:a0:24:ab:fb:9c;
-    send dhcp-lease-time 3600;
-    supersede domain-name "fugue.com rc.vix.com home.vix.com";
-    prepend domain-name-servers 127.0.0.1;
-    request subnet-mask, broadcast-address, time-offset, routers,
-	    domain-name, domain-name-servers, host-name;
-    require subnet-mask, domain-name-servers;
-}
-.Ed
-.Pp
-This is a very complicated
-.Nm
-file \- in general, yours should be much simpler.
-In many cases, it's sufficient to just create an empty
-.Nm
-file \- the defaults are usually fine.
 .Sh SEE ALSO
 .Xr dhclient.leases 5 ,
 .Xr dhcp-options 5 ,
 .Xr dhcpd.conf 5 ,
 .Xr dhclient 8 ,
 .Xr dhcpd 8
-.Sh STANDARDS
-.Rs
-.%A R. Droms
-.%D March 1997
-.%R RFC 2131
-.%T Dynamic Host Configuration Protocol
-.Re
-.Pp
-.Rs
-.%A S. Alexander
-.%A R. Droms
-.%D March 1997
-.%R RFC 2132
-.%T DHCP Options and BOOTP Vendor Extensions
-.Re
-.Sh AUTHORS
-.An -nosplit
-.Xr dhclient 8
-was written by
-.An Ted Lemon Aq Mt mellon@vix.com
-under a contract with Vixie Labs.
-.Pp
-The current implementation was reworked by
-.An Henning Brauer Aq Mt henning@openbsd.org .
diff --git a/sbin/dhclient/dhclient.leases.5 b/sbin/dhclient/dhclient.leases.5
index ed2b69ae489..b43b8bc7392 100644
--- a/sbin/dhclient/dhclient.leases.5
+++ b/sbin/dhclient/dhclient.leases.5
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: dhclient.leases.5,v 1.9 2013/07/16 09:45:28 schwarze Exp $
+.\"	$OpenBSD: dhclient.leases.5,v 1.10 2017/10/20 13:04:50 krw Exp $
 .\"
 .\" Copyright (c) 1997 The Internet Software Consortium.
 .\" All rights reserved.
@@ -36,7 +36,7 @@
 .\" see ``http://www.isc.org/isc''.  To learn more about Vixie
 .\" Enterprises, see ``http://www.vix.com''.
 .\"
-.Dd $Mdocdate: July 16 2013 $
+.Dd $Mdocdate: October 20 2017 $
 .Dt DHCLIENT.LEASES 5
 .Os
 .Sh NAME
@@ -52,7 +52,7 @@ The file is written as a log, so the last declaration is the most recent
 lease obtained.
 .Pp
 The lease file is named
-.Pa /var/db/dhclient.leases. Ns Aq Ar IFNAME ,
+.Pa /var/db/dhclient.leases . Ns Aq Ar IFNAME ,
 where
 .Qq IFNAME
 represents the network interface
@@ -64,12 +64,77 @@ is configured for the em0 network device,
 the lease file will be named
 .Pa /var/db/dhclient.leases.em0 ,
 .Pp
-The format of the lease declarations is described in
-.Xr dhclient.conf 5 .
+A lease statement has the format
+.Pp
+.D1 Ic lease No { Ar lease-declaration ; ... ; No }
+.Pp
+Where
+.Ar lease\-declaration
+is one of:
+.Pp
+.Bl -tag -width Ds -compact
+.It Ic bootp
+The lease was acquired using the
+BOOTP protocol rather than the DHCP protocol.
+.Pp
+.It Ic expire Ar date
+.It Ic rebind Ar date
+.It Ic renew Ar date
+.Ic expire
+defines when
+.Xr dhclient 8
+will no longer use the lease to configure the interface.
+.Ic rebind
+specifies when
+.Xr dhclient 8
+begins tring to renew the lease with broadcasts to any server.
+.Ic renew
+specifies when
+.Xr dhclient 8
+begins trying to renew the lease with unicasts to the originating server.
+.Pp
+Dates are specified in accordance with the
+.Xr strptime 3
+format:
+.Pp
+.D1 %w %Y/%m/%d \&%T UTC
+.Pp
+For example:
+.Pp
+.Dl renew 1 2017/10/16 14:03:49 UTC
+.Pp
+.It Ic filename Qq Ar string
+The boot filename.
+.Pp
+.It Ic fixed-address Ar ip-address
+The IPv4 address of the lease.
+This is required for all lease statements.
+The IPv4 address is specified as a dotted quad (e.g. 12.34.56.78).
+.Pp
+.It Ic interface Qq Ar string
+The interface on which the lease is valid.
+.Pp
+.It Ic next-server Ar ip-address
+The IPv4 address of the boot server.
+The IPv4 address is specified as a dotted quad (e.g. 12.34.56.78).
+.Pp
+.It Ic option Ar option option-value
+The value of
+.Ar option .
+DHCP options are described in
+.Xr dhcp-options 5 .
+.Pp
+.It Ic server-name Qq Ar string
+The name of the boot server.
+.Pp
+.It Ic ssid Qq Ar string
+The SSID to which the lease applies.
+.El
 .Sh FILES
 .Bl -tag -width "/var/db/dhclient.leases.IFNAME   "
-.It Pa /var/db/dhclient.leases. Ns Aq Ar IFNAME ,
-Current lease file.
+.It Pa /var/db/dhclient.leases . Ns Aq Ar IFNAME
+Persistent database of leases for
+.Aq Ar IFNAME .
 .El
 .Sh SEE ALSO
 .Xr dhclient.conf 5 ,
@@ -77,27 +142,3 @@ Current lease file.
 .Xr dhcpd.conf 5 ,
 .Xr dhclient 8 ,
 .Xr dhcpd 8
-.Sh STANDARDS
-.Rs
-.%A R. Droms
-.%D March 1997
-.%R RFC 2131
-.%T Dynamic Host Configuration Protocol
-.Re
-.Pp
-.Rs
-.%A S. Alexander
-.%A R. Droms
-.%D March 1997
-.%R RFC 2132
-.%T DHCP Options and BOOTP Vendor Extensions
-.Re
-.Sh AUTHORS
-.An -nosplit
-.Xr dhclient 8
-was written by
-.An Ted Lemon Aq Mt mellon@vix.com
-under a contract with Vixie Labs.
-.Pp
-The current implementation was reworked by
-.An Henning Brauer Aq Mt henning@openbsd.org .