diff --git a/weave b/weave
index 4b132a4e07..5b1cf5fea2 100755
--- a/weave
+++ b/weave
@@ -919,8 +919,9 @@ ipam_cidrs() {
         if [ "$IPAM_CIDRS" = "404 page not found" ] ; then
             echo "No IP address supplied (use the -iprange option on 'weave launch' to enable IP address allocation)" >&2
             return 1
-        elif [ "$IPAM_CIDRS" = "cancelled" ] ; then
-            return 0
+        elif ! is_cidr "$IPAM_CIDRS" ; then
+            echo "$IPAM_CIDRS" >&2
+            return 1
         fi
         ALL_CIDRS="$IPAM_CIDRS"
     fi
@@ -935,8 +936,6 @@ ipam_cidrs() {
             if [ "$CIDR" = "404 page not found" ] ; then
                 echo "IP address allocation must be enabled to use 'net:'" >&2
                 return 1
-            elif [ "$CIDR" = "cancelled" ] ; then
-                return 0
             elif ! is_cidr "$CIDR" ; then
                 echo "$CIDR" >&2
                 return 1
@@ -1489,10 +1488,6 @@ case "$COMMAND" in
         CONTAINER=$(container_id $1)
         create_bridge
         ipam_cidrs$ATTACH_TYPE $CONTAINER $CIDR_ARGS
-        if [ "$IPAM_CIDRS" = "cancelled" ] ; then
-            echo "cancelled" >&2
-            exit 0
-        fi
         if [ -n "$REWRITE_HOSTS" ] && command_exists weavehosts ; then
             PATH_AND_NAME=$(docker inspect -f '{{.HostsPath}} {{.Config.Hostname}}' $CONTAINER)
             weavehosts $PATH_AND_NAME $ALL_CIDRS