diff --git a/ulib/debian b/ulib/debian
index 6b8fcd9..e0ff057 100644
--- a/ulib/debian
+++ b/ulib/debian
@@ -68,6 +68,7 @@ function service_enable() {
 # Gestion des interfaces réseau
 
 __DEBIAN_NETWORK_DEVEL_SHOW_MODIFS=
+__DEBIAN_NETWORK_INTERFACES=/etc/network/interfaces
 
 function __network_parse_confbr() {
     local br; local -a ifaces
@@ -368,7 +369,7 @@ function network_interfaces_check_confbr() {
 
     local br="$1"
     local -a ifaces; array_copy ifaces __nicc_ifaces
-    local nifile="${3:-/etc/network/interfaces}"
+    local nifile="${3:-$__DEBIAN_NETWORK_INTERFACES}"
 
     awkrun <"$nifile" -f br="$br" ifaces[@]=__nicc_ifaces '
 BEGIN {
@@ -442,7 +443,7 @@ function network_interfaces_check_confip() {
 
     local iface="$1" gateway="$2"
     local -a ipsuffixes; array_copy ipsuffixes __nicc_ipsuffixes
-    local nifile="${4:-/etc/network/interfaces}"
+    local nifile="${4:-$__DEBIAN_NETWORK_INTERFACES}"
 
     awkrun <"$nifile" -f iface="$iface" gateway="$gateway" ipsuffixes[@]=ipsuffixes '
 BEGIN {
@@ -625,7 +626,7 @@ END {
 function network_interfaces_remove_iface() {
     # Supprimer dans le fichier $2(=/etc/network/interfaces) toute la
     # configuration qui concerne l'interface $1
-    local iface="$1" nifile="${2:-/etc/network/interfaces}"
+    local iface="$1" nifile="${2:-$__DEBIAN_NETWORK_INTERFACES}"
     local tmpfile; ac_set_tmpfile tmpfile
     local modified
 
@@ -642,7 +643,7 @@ function network_interfaces_remove_ifaces() {
     local -a __niri_ifaces; array_copy __niri_ifaces "${1:-ifaces}"
 
     local -a ifaces; array_copy ifaces __niri_ifaces
-    local nifile="${2:-/etc/network/interfaces}"
+    local nifile="${2:-$__DEBIAN_NETWORK_INTERFACES}"
     local workfile; ac_set_tmpfile workfile
     local tmpfile; ac_set_tmpfile tmpfile
     local iface modified
@@ -678,7 +679,7 @@ function network_interfaces_add_confip() {
 
     local iface="$1" gateway="$2"
     local -a ipsuffixes; array_copy ipsuffixes __niac_ipsuffixes
-    local nifile="${4:-/etc/network/interfaces}"
+    local nifile="${4:-$__DEBIAN_NETWORK_INTERFACES}"
     local mainip netmask method
 
     network_parse_ipsuffix "${ipsuffixes[0]}" mainip netmask
@@ -718,7 +719,7 @@ function network_interfaces_add_confbr() {
     local br="$1"
     local -a ifaces; array_copy ifaces __niac_ifaces
     local -a confips; array_copy confips __niac_confips
-    local nifile="${4:-/etc/network/interfaces}"
+    local nifile="${4:-$__DEBIAN_NETWORK_INTERFACES}"
     local iface confip
 
     for iface in "${ifaces[@]}"; do
@@ -1011,7 +1012,7 @@ function network_config() {
         if [ -n "$modify" ]; then
             # faire une copie de travail
             local interfaces; ac_set_tmpfile interfaces
-            cat /etc/network/interfaces >"$interfaces"
+            cat "$__DEBIAN_NETWORK_INTERFACES" >"$interfaces"
 
             if [ -n "$reset_interfaces" ]; then
                 echo >"$interfaces" "\
@@ -1031,7 +1032,7 @@ iface lo inet loopback
             done
             for confip in "${confips[@]}"; do
                 network_parse_confip "$confip" iface gateway ipsuffixes
-                network_interfaces_remove_iface "$iface"
+                network_interfaces_remove_iface "$iface" "$interfaces"
             done
 
             # puis recréer la configuration
@@ -1048,21 +1049,21 @@ iface lo inet loopback
 
             # Fin de traitement
             if [ -n "$__DEBIAN_NETWORK_DEVEL_SHOW_MODIFS" ]; then
-                if testdiff "$interfaces" /etc/network/interfaces; then
-                    uecho "Setting /etc/network/interfaces to:"
+                if testdiff "$interfaces" "$__DEBIAN_NETWORK_INTERFACES"; then
+                    uecho "Setting $__DEBIAN_NETWORK_INTERFACES to:"
                     cat "$interfaces" | sed 's/^/    /g' 1>&2
                 else
-                    uecho "/etc/network/interfaces: pas de modifications"
+                    uecho "$__DEBIAN_NETWORK_INTERFACES: pas de modifications"
                 fi
-            elif testdiff "$interfaces" /etc/network/interfaces; then
-                __network_backup /etc/network/interfaces
+            elif testdiff "$interfaces" "$__DEBIAN_NETWORK_INTERFACES"; then
+                __network_backup "$__DEBIAN_NETWORK_INTERFACES"
                 if show_debug; then
-                    edebug "Setting /etc/network/interfaces to:"
+                    edebug "Setting $__DEBIAN_NETWORK_INTERFACES to:"
                     cat "$interfaces" | sed 's/^/    /g' 1>&2
                 else
-                    estep /etc/network/interfaces
+                    estep "$__DEBIAN_NETWORK_INTERFACES"
                 fi
-                cat "$interfaces" >/etc/network/interfaces
+                cat "$interfaces" >"$__DEBIAN_NETWORK_INTERFACES"
                 modified=1
             fi
             ac_clean "$interfaces"