diff --git a/src/steps-postinstall/20-nfs.sh b/src/steps-postinstall/20-nfs.sh
index 802167d..e1ce711 100644
--- a/src/steps-postinstall/20-nfs.sh
+++ b/src/steps-postinstall/20-nfs.sh
@@ -1,10 +1,37 @@
 #!/usr/bin/env bash
 
+# $1	The path to ensure is mounted after a network interface comes up.
+ensure_nfs() {
+	local dirpath="${1}";
+	local target_script="/etc/network/if-up.d/ensure-nfs";
+	#/etc/network/if-up.d/
+	
+	task_begin "ensure_nfs: registering ${dirpath}";
+	# 1: Ensure the target script exists
+	if [[ ! -d "$(dirname "${target_script}")" ]]; then
+		mkdir -p "$(dirname "${target_script}")";
+	fi
+	if [[ ! -r "${target_script}" ]]; then
+		echo "#!/usr/bin/env bash" >>"${target_script}";
+		chmod +x "${target_script}";
+	fi
+	
+	if grep -q "${dirpath}; then" "${target_script}"; then
+		echo "ensure_nfs: ${dirpath} is already registered.";
+		task_end 0;
+		return 0;
+	fi
+	
+	echo "if ! mountpoint -q '${dirpath}'; then mount '${dirpath}'; fi" >>"${target_script}";
+	
+	task_end "$?" "ensure_nfs: error registering ${dirpath} in ${target_script}";
+}
+
 # $1	Thing to mount
 # $2	Path to mount it to
 add_nfs_mount() {
-	source="${1}";
-	target="${2}";
+	local source="${1}";
+	local target="${2}";
 	
 	task_begin "NFS mount ${source} → ${target}";
 	# 1: Remove any old entries from /etc/fstab
@@ -18,6 +45,8 @@ add_nfs_mount() {
 	mount "${target}";
 	
 	task_end "$?";
+	
+	ensure_nfs "${target}";
 }
 
 add_nfs_mount "magicbag.node.mooncarrot.space:/mnt/elfstone2/cluster" "/mnt/shared";