Différences

Ci-dessous, les différences entre deux révisions de la page.

--- 090_applicatifs:165dhcp:30-client_dhcp [le 16/02/2025 à 14:36] – supprimée - modification externe (Date inconnue) 127.0.0.1
+++ 090_applicatifs:165dhcp:30-client_dhcp [le 23/03/2025 à 09:40] (Version actuelle) – [La mémoire du client] prof
@@ Ligne 1: / Ligne 1: @@
+====== Le client DHCP d'ISC ======
+Sur Debian 12 (Bookworm), le client dhcp installé par défaut est le client d'isc: ''isc-dhcp-client''. Ce client dispose d'un fichier de configuration ''/etc/dhcp/dhclient.conf''. Comparons les configurations sur «nas» et «democlient1»
+===== Configuration =====
+==== nas ====
+Version expurgée des commentaires:
+<html><pre class="code">
+option rfc3442-classless-static-routes code 121 = array of unsigned integer 8;
+send host-name = gethostname();
+<span class="hly">request subnet-mask, broadcast-address, time-offset, routers,
+        domain-name, domain-name-servers, domain-search, <b>host-name,
+        dhcp6.name-servers, dhcp6.domain-search, dhcp6.fqdn, dhcp6.sntp-servers,
+        netbios-name-servers, netbios-scope, interface-mtu,</b>
+        rfc3442-classless-static-routes, ntp-servers;</span>
+</pre></html>
+Ce fichier n'a pas été modifié, c'est donc la configuration par défaut.
+Toutes les options en gras sont inutiles dans notre contexte. Elles ont été supprimées dans le fichier de configuration sur «democlient1»
+==== democlient1 ====
+<html><pre class="code">
+option rfc3442-classless-static-routes code 121 = array of unsigned integer 8;
+send host-name = gethostname();
+<span class="hly">request subnet-mask, broadcast-address, time-offset, routers,
+        domain-name, domain-name-servers, domain-search,
+        rfc3442-classless-static-routes, ntp-servers;</span>
+<span class="bhlo">send dhcp-client-identifier 1:52:54:00:b7:66:81;</span>
+</pre></html>
+En revanche, ici le client envoie explicitement sa seule adresse MAC comme CID, ce qui explique l'apparente anomalie constatée page précédente.
+===== La mémoire du client =====
+isc-dhcp-client a de la mémoire. Elle est écrite dans le fichier ''/var/lib/dhcp/dhclient.enp1s0.leases''. Voyons la mémoire du nas:
+<html><pre class="code">
+cat dhclient.enp1s0.leases
+default-duid "\000\001\000\001/qNjRT\000\322\232\016";
+lease {
+  interface "enp1s0";
+  fixed-address 192.168.61.2;
+  option subnet-mask 255.255.255.0;
+  option dhcp-lease-time 3600;
+  option routers 192.168.61.1;
+  option dhcp-message-type 5;
+  option dhcp-server-identifier 192.168.61.1;
+  option domain-name-servers 192.168.61.1;
+  option domain-search "home.nain-t.net.";
+  option dhcp-renewal-time 1800;
+  option dhcp-rebinding-time 2700;
+  option host-name "nas";
+  option dhcp-client-identifier ff:0:d2:9a:e:0:1:0:1:2f:71:4e:6a:52:54:0:d2:9a:e;
+  renew 6 2025/03/22 11:04:54;
+  rebind 6 2025/03/22 11:20:11;
+  expire 6 2025/03/22 11:35:11;
+}
+lease {
+  interface "enp1s0";
+  fixed-address 192.168.61.2;
+  option subnet-mask 255.255.255.0;
+  option dhcp-lease-time 3600;
+  option routers 192.168.61.1;
+  option dhcp-message-type 5;
+  option dhcp-server-identifier 192.168.61.1;
+  option domain-name-servers 192.168.61.1;
+  option domain-search "home.nain-t.net.";
+  option dhcp-renewal-time 1800;
+  option dhcp-rebinding-time 2700;
+  option host-name "nas";
+  option dhcp-client-identifier ff:0:d2:9a:e:0:1:0:1:2f:71:4e:6a:52:54:0:d2:9a:e;
+  renew 6 2025/03/22 11:29:41;
+  rebind 6 2025/03/22 11:49:54;
+  expire 6 2025/03/22 12:04:54;
+}
+lease {
+  interface "enp1s0";
+  fixed-address 192.168.61.2;
+  option subnet-mask 255.255.255.0;
+  option dhcp-lease-time 3600;
+  option routers 192.168.61.1;
+  option dhcp-message-type 5;
+  option dhcp-server-identifier 192.168.61.1;
+  option domain-name-servers 192.168.61.1;
+  option domain-search "home.nain-t.net.";
+  option dhcp-renewal-time 1800;
+  option dhcp-rebinding-time 2700;
+  option host-name "nas";
+  option dhcp-client-identifier ff:0:d2:9a:e:0:1:0:1:2f:71:4e:6a:52:54:0:d2:9a:e;
+  renew 6 2025/03/22 11:54:35;
+  rebind 6 2025/03/22 12:14:41;
+  expire 6 2025/03/22 12:29:41;
+}
+lease {
+  interface "enp1s0";
+  fixed-address 192.168.61.2;
+  option subnet-mask 255.255.255.0;
+  option dhcp-lease-time 3600;
+  option routers 192.168.61.1;
+  option dhcp-message-type 5;
+  option dhcp-server-identifier 192.168.61.1;
+  option domain-name-servers 192.168.61.1;
+  option domain-search "home.nain-t.net.";
+  option dhcp-renewal-time 1800;
+  option dhcp-rebinding-time 2700;
+  option host-name "nas";
+  option dhcp-client-identifier ff:0:d2:9a:e:0:1:0:1:2f:71:4e:6a:52:54:0:d2:9a:e;
+  renew 6 2025/03/22 12:21:31;
+  rebind 6 2025/03/22 12:39:35;
+  expire 6 2025/03/22 12:54:35;
+}
+lease {
+  interface "enp1s0";
+  fixed-address 192.168.61.2;
+  option subnet-mask 255.255.255.0;
+  option dhcp-lease-time 3600;
+  option routers 192.168.61.1;
+  option dhcp-message-type 5;
+  option dhcp-server-identifier 192.168.61.1;
+  option domain-name-servers 192.168.61.1;
+  option domain-search "home.nain-t.net.";
+  option dhcp-renewal-time 1800;
+  option dhcp-rebinding-time 2700;
+  option host-name "nas";
+  option dhcp-client-identifier ff:0:d2:9a:e:0:1:0:1:2f:71:4e:6a:52:54:0:d2:9a:e;
+  renew 6 2025/03/22 12:46:46;
+  rebind 6 2025/03/22 13:06:31;
+  expire 6 2025/03/22 13:21:31;
+}
+lease {
+  interface "enp1s0";
+  fixed-address 192.168.61.2;
+  option subnet-mask 255.255.255.0;
+  option dhcp-lease-time 3600;
+  option routers 192.168.61.1;
+  option dhcp-message-type 5;
+  option dhcp-server-identifier 192.168.61.1;
+  option domain-name-servers 192.168.61.1;
+  option domain-search "home.nain-t.net.";
+  option dhcp-renewal-time 1800;
+  option dhcp-rebinding-time 2700;
+  option host-name "nas";
+  option dhcp-client-identifier ff:0:d2:9a:e:0:1:0:1:2f:71:4e:6a:52:54:0:d2:9a:e;
+  <span class="hly">renew 6 2025/03/22 13:14:36;</span>
+  <span class="hlo">rebind 6 2025/03/22 13:31:46;</span>
+  <span class="hlr">expire 6 2025/03/22 13:46:46;</span>
+}
+</pre></html>
+Le serveur était hors service et le client a perdu son adresse, mais il l'a récupérée aux alentours de 14:18:47 - 30 minutes soit 13:48:47. L'interruption a été de courte durée.
+<html><pre class="code">
+lease {
+  interface "enp1s0";
+  fixed-address 192.168.61.2;
+  option subnet-mask 255.255.255.0;
+  option dhcp-lease-time 3600;
+  option routers 192.168.61.1;
+  option dhcp-message-type 5;
+  option dhcp-server-identifier 192.168.61.1;
+  option domain-name-servers 192.168.61.1;
+  option domain-search "home.nain-t.net.";
+  option dhcp-renewal-time 1800;
+  option dhcp-rebinding-time 2700;
+  option host-name "nas";
+  option dhcp-client-identifier ff:0:d2:9a:e:0:1:0:1:2f:71:4e:6a:52:54:0:d2:9a:e;
+  <span class="hly">renew 6 2025/03/22 14:18:47;</span>
+  rebind 6 2025/03/22 14:38:28;
+  expire 6 2025/03/22 14:53:28;
+}
+lease {
+  interface "enp1s0";
+  fixed-address 192.168.61.2;
+  option subnet-mask 255.255.255.0;
+  option dhcp-lease-time 3600;
+  option routers 192.168.61.1;
+  option dhcp-message-type 5;
+  option dhcp-server-identifier 192.168.61.1;
+  option domain-name-servers 192.168.61.1;
+  option domain-search "home.nain-t.net.";
+  option dhcp-renewal-time 1800;
+  option dhcp-rebinding-time 2700;
+  option host-name "nas";
+  option dhcp-client-identifier ff:0:d2:9a:e:0:1:0:1:2f:71:4e:6a:52:54:0:d2:9a:e;
+  renew 6 2025/03/22 14:48:17;
+  rebind 6 2025/03/22 15:03:47;
+  expire 6 2025/03/22 15:18:47;
+}
+lease {
+  interface "enp1s0";
+  fixed-address 192.168.61.2;
+  option subnet-mask 255.255.255.0;
+  option dhcp-lease-time 3600;
+  option routers 192.168.61.1;
+  option dhcp-message-type 5;
+  option dhcp-server-identifier 192.168.61.1;
+  option domain-name-servers 192.168.61.1;
+  option domain-search "home.nain-t.net.";
+  option dhcp-renewal-time 1800;
+  option dhcp-rebinding-time 2700;
+  option host-name "nas";
+  option dhcp-client-identifier ff:0:d2:9a:e:0:1:0:1:2f:71:4e:6a:52:54:0:d2:9a:e;
+  renew 6 2025/03/22 15:13:52;
+  rebind 6 2025/03/22 15:33:17;
+  expire 6 2025/03/22 15:48:17;
+}
+lease {
+  interface "enp1s0";
+  fixed-address 192.168.61.2;
+  option subnet-mask 255.255.255.0;
+  option dhcp-lease-time 3600;
+  option routers 192.168.61.1;
+  option dhcp-message-type 5;
+  option dhcp-server-identifier 192.168.61.1;
+  option domain-name-servers 192.168.61.1;
+  option domain-search "home.nain-t.net.";
+  option dhcp-renewal-time 1800;
+  option dhcp-rebinding-time 2700;
+  option host-name "nas";
+  option dhcp-client-identifier ff:0:d2:9a:e:0:1:0:1:2f:71:4e:6a:52:54:0:d2:9a:e;
+  renew 6 2025/03/22 15:40:37;
+  rebind 6 2025/03/22 15:58:52;
+  expire 6 2025/03/22 16:13:52;
+}
+lease {
+  interface "enp1s0";
+  fixed-address 192.168.61.2;
+  option subnet-mask 255.255.255.0;
+  option dhcp-lease-time 3600;
+  option routers 192.168.61.1;
+  option dhcp-message-type 5;
+  option dhcp-server-identifier 192.168.61.1;
+  option domain-name-servers 192.168.61.1;
+  option domain-search "home.nain-t.net.";
+  option dhcp-renewal-time 1800;
+  option dhcp-rebinding-time 2700;
+  option host-name "nas";
+  option dhcp-client-identifier ff:0:d2:9a:e:0:1:0:1:2f:71:4e:6a:52:54:0:d2:9a:e;
+  renew 6 2025/03/22 16:06:35;
+  rebind 6 2025/03/22 16:25:37;
+  expire 6 2025/03/22 16:40:37;
+}
+lease {
+  interface "enp1s0";
+  fixed-address 192.168.61.2;
+  option subnet-mask 255.255.255.0;
+  option dhcp-lease-time 3600;
+  option routers 192.168.61.1;
+  option dhcp-message-type 5;
+  option dhcp-server-identifier 192.168.61.1;
+  option domain-name-servers 192.168.61.1;
+  option domain-search "home.nain-t.net.";
+  option dhcp-renewal-time 1800;
+  option dhcp-rebinding-time 2700;
+  option host-name "nas";
+  option dhcp-client-identifier ff:0:d2:9a:e:0:1:0:1:2f:71:4e:6a:52:54:0:d2:9a:e;
+  renew 6 2025/03/22 16:29:12;
+  rebind 6 2025/03/22 16:51:35;
+  expire 6 2025/03/22 17:06:35;
+}
+</pre></html>
+Le client garde donc en mémoire les baux qu'il a récupéré dans le passé proche.