http://www.randombugs.com/linux/linux-isc-dhcp-server-failover-debian-ubuntu.html

           #
           # /etc/dhcpd.conf for primary DHCP server
           #

           server-identifier firmadhcp.firma.cz;
           authoritative;
           option domain-name "firma.cz";
           option domain-search "firma.cz";
           option netbios-node-type 8;
           option time-offset 1;
           log-facility local0;
           option rfc3442-classless-static-routes code 121 = array of integer 8;
           option ms-classless-static-routes code 249 = array of integer 8;
           ddns-update-style none;

           failover peer "dhcp-failover" {
             primary; # declare this to be the primary server
             address 192.168.10.115;
             port 647;
             peer address 192.168.10.97;
             peer port 647;
             max-response-delay 1440;
             max-unacked-updates 10;
             load balance max seconds 3;
             mclt 86400;
             split 128;
           }
           ####  Sit firma

           host bubenec01 {
                 hardware ethernet 00:15:17:8A:0A:E4;
                 fixed-address 192.168.10.118;
                 }

           group {
              subnet 192.168.10.0 netmask 255.255.255.0 {
                 option routers 192.168.10.1;
                 option domain-name-servers 192.168.10.20, 192.168.10.118, 192.168.10.1;
                 default-lease-time 604800;
                 max-lease-time 259200;
                 # Nastaveni route - Prcice
                 option rfc3442-classless-static-routes 32, 10, 0, 0, 23, 192, 168, 10, 11, 0, 192, 168, 10, 1;
                 option ms-classless-static-routes 32, 10, 0, 0, 23, 192, 168, 10, 11, 0, 192, 168, 10, 1;
                 pool {
                     failover peer "dhcp-failover";
                     max-lease-time 86400; # 30 minutes
                     range 192.168.10.101 192.168.10.220;
                   }
              }
           }

           #
           # /etc/dhcpd.conf for secondary DHCP server
           #

           server-identifier firmadhcp.firma.cz;
           authoritative;
           option domain-name "firma.cz";
           option domain-search "firma.cz";
           option netbios-node-type 8;
           option time-offset 1;
           log-facility local0;
           option rfc3442-classless-static-routes code 121 = array of integer 8;
           option ms-classless-static-routes code 249 = array of integer 8;
           ddns-update-style none;

           failover peer "dhcp-failover" {
             secondary; # declare this to be the secondary server
             address 192.168.10.97;
             port 647;
             peer address 192.168.10.115;
             peer port 647;
             max-response-delay 1440;
             max-unacked-updates 10;
             load balance max seconds 3;
           }

           ####  Sit firma

           host bubenec01 {
                 hardware ethernet 00:15:17:8A:0A:E4;
                 fixed-address 192.168.10.118;
                 }

           group {
              subnet 192.168.10.0 netmask 255.255.255.0 {
                 option routers 192.168.10.1;
                 option domain-name-servers 192.168.10.20, 192.168.10.118, 192.168.10.1;
                 default-lease-time 604800;
                 max-lease-time 259200;
                 # Nastaveni route - Prcice
                 option rfc3442-classless-static-routes 32, 10, 0, 0, 23, 192, 168, 10, 11, 0, 192, 168, 10, 1;
                 option ms-classless-static-routes 32, 10, 0, 0, 23, 192, 168, 10, 11, 0, 192, 168, 10, 1;
                 pool {
                     failover peer "dhcp-failover";
                     max-lease-time 86400; # 30 minutes
                     range 192.168.10.101 192.168.10.220;
                   }
              }
           }

V konfiguraci se musí lišit položka host

 # NB002
      host nb002_wireless {
      hardware ethernet 40:f0:2f:67:4d:42;
      fixed-address 10.0.3.171;
      }
      host nb002_wired {
      hardware ethernet a4:5d:36:9c:f1:0a;
      fixed-address 10.0.3.171;
      }

Ve Windows 7 a novějších verzích OS nelze získat adresu z DHCP serveru. Vypadá to, že problém je v parametru server-identifier, pro který není odpovídající záznam v DNS.

Po adstranění parametru lze získat adresu bez problému.

#server-identifier fw.props.local;
authoritative;
option domain-name "props.local";
option netbios-node-type 8;
option time-offset 1;
log-facility local0;
ddns-update-style none;
include "/etc/dhcp/hosts.cfg";
subnet 192.168.15.0 netmask 255.255.255.0 {
   #filename "pxelinux.0";
   #next-server 192.168.15.10;
   range 192.168.15.150 192.168.15.200;
   option routers 192.168.15.10;
   option domain-name-servers 192.168.15.10;
   option broadcast-address 192.168.15.255;
   default-lease-time 604800;
   max-lease-time 259201;
}

http://serverfault.com/questions/37451/dhcp-logging-host-declarations-in-log-file

Doplnit změnu v rsyslog.conf(použito ve škole)

if known { 
    log (info, concat ("HOSTNAME: ", host-decl-name, " on ",binary-to-ascii (10, 8, ".", leased-address)," at ", binary-to-ascii (16, 8, ":", substring (hardware, 1, 6)))); 
}

ssh/config

host hplx05.grupteam.local
   hostname hplx05.grupteam.local
   user novak
   identityfile /root/.ssh/id_rsa
   compression yes
   protocol 2

dhcprsync

#! /bin/bash -l
 
 
FILE=$HOSTNAME"_dhcpcfg_"$(date +%d%m%Y_%H-%M-%S)
tar -czf /tmp/$FILE.tgz /etc/dhcp/dhcpd.conf /etc/dhcp/hosts.cfg
mv /tmp/$FILE.tgz /etc/dhcp/
 
rsync -avzh novak@hplx05.grupteam.local:/etc/dhcp/hosts.cfg /etc/dhcp/hplx05_bck
rsync -avzh novak@hplx05.grupteam.local:/etc/dhcp/dhcpd.conf /etc/dhcp/hplx05_bck
rsync -avzh /etc/dhcp/$FILE.tgz novak@hplx05.grupteam.local:/etc/dhcp/
rsync -avzh /etc/dhcp/hosts.cfg novak@hplx05.grupteam.local:/etc/dhcp/hosts.cfg
 
/etc/init.d/isc-dhcp-server restart
ssh novak@hplx05.grupteam.local 'sudo /etc/init.d/isc-dhcp-server restart'

sudoers

novak  ALL=(ALL) NOPASSWD: /etc/init.d/isc-dhcp-server restart