Dynamic Host Configuration Protocol

Service sur le port 67 en UDP (bootps)
Client sur le port 68 en UDP (bootpc)
Liste des options de configuration disponibles:
Options DHCP

Debian

tcpdump -n -i {iface} port bootpc or port bootps

DHCP service

isc-dhcp-server /var/lib/dhcp/dhcpd.leases

/etc/dhcp/dhcpd.conf

option domain-name "michel-joly.fr";
option domain-name-servers ns1.michel-joly.fr;
option domain-search "michel-joly.fr";

default-lease-time 28200;
max-lease-time 28800;

subnet 192.168.42.0 netmask 255.255.255.0 {
       range 192.168.42.100 192.168.42.130;
       option routers 192.168.42.254;

}

host workstation{
     hardware ethernet 70:85:c2:fc:8b:b0;
     fixed-address     192.168.42.1;
}

Classes DHCP

# Le sous réseau auquel appartient notre serveur DHCP
subnet 192.168.42.0 netmask 255.255.255.0 {
    range 192.168.42.1 192.168.42.99;
    option domain-name-servers 192.168.42.250,192.168.42.251;
    option domain-name "mic.local";
    option routers 192.168.42.254;
    default-lease-time 28200;
    max-lease-time 28800;
}

class "class1"{
    match if substring (option user-class,0,6)="class1";
}

# Le deuxième sous-réseau : la configuration reste la même que pour un sous réseau # normal, avec les mêmes possibilités d’options
subnet 192.168.142.0 netmask 255.255.255.0 {
    option domain-name-servers 192.168.42.250, 192.168.42.251;
    option routers 192.168.142.254;
    pool {
        allow members of "class1";
        range 192.168.42.100 192.168.42.110;
        option domain-name "class1.local";
        #on donne la passerelle aux clients de la class1
        option routers 192.168.42.254;
    }

    pool {
        allow unknown-clients;
        deny members of "class1";
        range 192.168.42.200 192.168.42.240;
        option domain-name "visiteurs.local";
    }
}

Debian DHCP relay

isc-dhcp-relay

Le fichier de configuration :

/etc/default/isc-dhcp-relay

# What servers should the DHCP relay forward requests to?
SERVERS="192.168.42.250"

# On what interfaces should the DHCP relay (dhrelay) serve DHCP requests?
INTERFACES="enp0s8 enp0s3"

Client

/etc/dhcp/dhclient.conf

dhclient -r {iface}
dhclient {iface}

Windows

Transfert de configuration en powershell

Export-DHCPServer -ComputerName {former_dhcp_server} -File {file_path.xml}
Import-DHCPServer -File {file_path.xml} -BackupPath

Cisco

Configuration

> en
# conf t
# (config) service dhcp
# (config) ip dhcp pool {nom}
# (dhcp-config) network {adresse_reseau} {masque}
# (dhcp-config) default-router {adresse_passerelle}
# (dhcp-config) dns-server {ip}
# (dhcp-config) option {num_option} 

Status et Capture de paquet

Configuration des reseaux DHCP

> en 
# conf t
# (config) show ip dhcp pool

capture des requetes

# (config-if) ip dhcp snooping [vlan {vlan_id}]
# (config-if) ip dhcp snooping information option

# (config) show ip dhcp snooping database [detail]