Reference: https://src.fedoraproject.org/rpms/dhcp/blob/rawhide/f/0006-Various-man-page-only-fixes.patch
From d359a7dc30e0423f9b90129291538cad1ee6a6d9 Mon Sep 17 00:00:00 2001
From: Pavel Zhukov <[email protected]>
Date: Thu, 21 Feb 2019 10:25:53 +0100
Subject: [PATCH 06/28] Various man-page-only fixes

---
 client/dhclient-script.8 | 22 +++++++++++++++++++++-
 client/dhclient.conf.5   | 14 +++++++++++++-
 common/dhcp-options.5    | 15 +++++++++++++++
 server/dhcpd.conf.5      | 14 +++++++++-----
 4 files changed, 58 insertions(+), 7 deletions(-)

diff --git a/client/dhclient-script.8 b/client/dhclient-script.8
index 5e5bd3d..37ecdc5 100644
--- a/client/dhclient-script.8
+++ b/client/dhclient-script.8
@@ -43,7 +43,7 @@ customizations are needed, they should be possible using the enter and
 exit hooks provided (see HOOKS for details).   These hooks will allow the
 user to override the default behaviour of the client in creating a
 .B /etc/resolv.conf
-file.
+file, and to handle DHCP options not handled by default.
 .PP
 No standard client script exists for some operating systems, even though
 the actual client may work, so a pioneering user may well need to create
@@ -87,6 +87,26 @@ present.   The
 .B ETCDIR/dhclient-exit-hooks
 script can modify the valid of exit_status to change the exit status
 of dhclient-script.
+.PP
+Immediately after dhclient brings an interface UP with a new IP address,
+subnet mask, and routes, in the REBOOT/BOUND states, it will check for the
+existence of an executable
+.B ETCDIR/dhclient-up-hooks
+script, and source it if found. This script can handle DHCP options in
+the environment that are not handled by default. A per-interface.
+.B ETCDIR/dhclient-${IF}-up-hooks
+script will override the generic script and be sourced when interface
+$IF has been brought up.
+.PP
+Immediately before dhclient brings an interface DOWN, removing its IP
+address, subnet mask, and routes, in the STOP/RELEASE  states, it will
+check for the existence of an executable
+.B ETCDIR/dhclient-down-hooks
+script, and source it if found. This script can handle DHCP options in
+the environment that are not handled by default. A per-interface
+.B ETCDIR/dhclient-${IF}-down-hooks
+script will override the generic script and be sourced when interface
+$IF is about to be brought down.
 .SH OPERATION
 When dhclient needs to invoke the client configuration script, it
 defines a set of variables in the environment, and then invokes
diff --git a/client/dhclient.conf.5 b/client/dhclient.conf.5
index dbe6f7e..8bac980 100644
--- a/client/dhclient.conf.5
+++ b/client/dhclient.conf.5
@@ -228,7 +228,8 @@ responding to the client send the client its values for the specified
 options.  Only the option names should be specified in the request
 statement - not option parameters.  By default, the DHCPv4 client
 requests the subnet-mask, broadcast-address, time-offset, routers,
-domain-name, domain-name-servers and host-name options while the DHCPv6
+domain-search, domain-name, domain-name-servers, host-name, nis-domain,
+nis-servers, ntp-servers and interface-mtu options while the DHCPv6
 client requests the dhcp6 name-servers and domain-search options.  Note
 that if you enter a \'request\' statement, you over-ride these defaults
 and these options will not be requested.
@@ -735,6 +736,17 @@ broadcast packets transmitted by DHCP clients, but is only useful if you
 know the DHCP service(s) anycast MAC address prior to configuring your
 client.  The \fIlink-type\fR and \fImac-address\fR parameters are configured
 in a similar manner to the \fBhardware\fR statement.
+.PP
+ \fBbootp-broadcast-always;\fR
+.PP
+The
+.B bootp-broadcast-always
+statement instructs dhclient to always set the bootp broadcast flag in
+request packets, so that servers will always broadcast replies.
+This is equivalent to supplying the dhclient -B argument, and has
+the same effect as specifying 'always-broadcast' in the server's dhcpd.conf.
+This option is provided as an extension to enable dhclient to work
+on IBM s390 Linux guests.
 .PP
 .SH SAMPLE
 The following configuration file was used on a laptop running NetBSD
diff --git a/common/dhcp-options.5 b/common/dhcp-options.5
index 51f80f7..a784b32 100644
--- a/common/dhcp-options.5
+++ b/common/dhcp-options.5
@@ -1075,6 +1075,21 @@ classless IP routing - it does not include a subnet mask.  Since
 classless IP routing is now the most widely deployed routing standard,
 this option is virtually useless, and is not implemented by any of the
 popular DHCP clients, for example the Microsoft DHCP client.
+.PP
+NOTE to Fedora dhclient users:
+.br
+dhclient-script interprets trailing 0 octets of the target as indicating
+the subnet class of the route, so for the following static-routes value:
+.br
+        option static-routes 172.0.0.0 172.16.2.254,
+.br
+                             192.168.0.0 192.168.2.254;
+.br
+dhclient-script will create routes:
+.br
+        172/8 via 172.16.2.254 dev $interface
+.br
+        192.168/16 via 192.168.2.254 dev $interface
 .RE
 .PP
 .nf
diff --git a/server/dhcpd.conf.5 b/server/dhcpd.conf.5
index 691e5dd..b7e79ea 100644
--- a/server/dhcpd.conf.5
+++ b/server/dhcpd.conf.5
@@ -527,6 +527,9 @@ pool {
 };
 .fi
 .PP
+Dynamic BOOTP leases are not compatible with failover, and, as such,
+you need to disallow BOOTP in pools that you are using failover for.
+.PP
 The  server currently  does very  little  sanity checking,  so if  you
 configure it wrong, it will just  fail in odd ways.  I would recommend
 therefore that you either do  failover or don't do failover, but don't
@@ -541,9 +544,9 @@ primary server might look like this:
 failover peer "foo" {
   primary;
   address anthrax.rc.example.com;
-  port 519;
+  port 647;
   peer address trantor.rc.example.com;
-  peer port 520;
+  peer port 847;
   max-response-delay 60;
   max-unacked-updates 10;
   mclt 3600;
@@ -1323,7 +1326,7 @@ the zone containing PTR records - for ISC BIND, something like this:
 .PP
 .nf
 key DHCP_UPDATER {
-  algorithm HMAC-MD5.SIG-ALG.REG.INT;
+  algorithm hmac-md5;
   secret pRP5FapFoJ95JEL06sv4PQ==;
 };
 
@@ -1346,7 +1349,7 @@ dhcpd.conf file:
 .PP
 .nf
 key DHCP_UPDATER {
-  algorithm HMAC-MD5.SIG-ALG.REG.INT;
+  algorithm hmac-md5;
   secret pRP5FapFoJ95JEL06sv4PQ==;
 };
 
@@ -2918,7 +2921,8 @@ statement
 The \fInext-server\fR statement is used to specify the host address of
 the server from which the initial boot file (specified in the
 \fIfilename\fR statement) is to be loaded.  \fIServer-name\fR should
-be a numeric IP address or a domain name.
+be a numeric IP address or a domain name.  If no \fInext-server\fR statement
+applies to a given client, the address 0.0.0.0 is used.
 .RE
 .PP
 The
-- 
2.35.1