diff --git a/HowtoDebian/Reseau.md b/HowtoDebian/Reseau.md
index d712f5a9..d08cc0da 100644
--- a/HowtoDebian/Reseau.md
+++ b/HowtoDebian/Reseau.md
@@ -203,6 +203,97 @@ De façon définitive :
 # ifconfig eth0 hw ether 01:23:45:67:89:0a
 ~~~
 
+## Migrer de networkd à ifup
+
+À partir de Stretch, certaines machines sont installés d'office avec networkd (qui fait partie de systemd), on peut vouloir migrer à ifup (/etc/network/interfaces) pour plusieurs raisons (compatibilité, …).
+Voici les opérations à faire :
+
+- On récupère les informations avec `networkctl status nomInterface` ;
+- On construit le fichier `/etc/network/interfaces` avec les informations récupérés (se baser sur un existant par exemple) ;
+- On désactive systemd-networkd et on restart networking :
+
+~~~
+# systemctl stop systemd-networkd.service; systemctl disable systemd-networkd.service; systemctl restart networking
+~~~
+
+Un exemple de conversion :
+
+~~~
+# networkctl status eno1
+● 2: eno1
+       Link File: /etc/systemd/network/50-public-interface.link
+    Network File: /etc/systemd/network/50-default.network
+            Type: ether
+           State: routable (failed)
+            Path: pci-0000:03:00.0
+          Driver: igb
+          Vendor: Intel Corporation
+           Model: I210 Gigabit Network Connection
+      HW Address: 00:01:02:03:04:05 (Intel Corporate)
+         Address: 192.0.2.100
+                  2001:db8::100
+         Gateway: 192.0.2.254 (Cisco Systems, Inc)
+                  fe80::12bd:18ff:ffff:ffff (Cisco Systems, Inc)
+             DNS: 127.0.0.1
+                  192.0.2.254
+             NTP: ntp.ovh.net
+
+cat /etc/systemd/network/50-default.network
+# This file sets the IP configuration of the primary (public) network device.
+# You can also see this as "OSI Layer 3" config.
+# It was created by the OVH installer, please be careful with modifications.
+# Documentation: man systemd.network or https://www.freedesktop.org/software/systemd/man/systemd.network.html
+
+[Match]
+MACAddress=00:01:02:03:04:05
+
+[Network]
+Description=network interface on public network, with default route
+DHCP=no
+Address=192.0.2.100/24
+Gateway=192.0.2.254
+#IPv6AcceptRA=false
+NTP=ntp.ovh.net
+DNS=127.0.0.1
+DNS=192.0.2.254
+Gateway=2001:41d0:0002:f5ff:ff:ff:ff:ff
+
+[Address]
+Address=2001:41d0:0002:f55c::/64
+
+[Route]
+Destination=2001:41d0:0002:f5ff:ff:ff:ff:ff
+Scope=link
+~~~
+
+On reporte dans `/etc/network/interfaces` :
+
+~~~
+# This file describes the network interfaces available on your system
+# and how to activate them. For more information, see interfaces(5).
+
+# The loopback network interface
+iface lo inet loopback
+
+# The primary network interface
+auto eno1
+iface eno1 inet static
+  address 192.0.2.100/24
+  gateway 192.0.2.254
+
+iface eno1 inet6 static
+  address 2001:db8::100/64
+  gateway 2001:41d0:0002:f5ff:ff:ff:ff:ff
+  post-up /sbin/ip -6 route add 2001:41d0:0002:f5ff:ff:ff:ff:ff dev eno1
+  post-up /sbin/ip -6 route add default via 2001:41d0:0002:f5ff:ff:ff:ff:ff
+~~~
+
+On désactive/stop networkd et on relance le service networking :
+
+~~~
+# systemctl stop systemd-networkd.service; systemctl disable systemd-networkd.service; systemctl restart networking
+~~~
+
 ## FAQ
 
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