diff --git a/src/main.rs b/src/main.rs
index d6eb3b9..c0c8800 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -159,20 +159,36 @@ fn roa_filter(roas: Vec<ROA>, filters: Vec<ROAFilter>) -> Vec<ROA> {
             }
         }
 
-        print!("1");
+        println!("# warning: dropped {:?}", roa);
         return None;
-    }).filter(|(_roa, filter)|
+    }).filter(|(roa, filter)|
         /* drop roa if the filter isn't permit */
         match filter.action {
             ROAFilterAction::Permit => true,
-            ROAFilterAction::Deny => false,
+            ROAFilterAction::Deny => {
+                println!("# warning: dropped {:?}", roa);
+                return false;
+            }
         }
-    ).map(|(roa, filter)| {
-        ROA {
+    ).filter_map(|(roa, filter)| {
+        if roa.route.network_length() > filter.maxlen {
+            println!("# warning: dropped {:?}", roa);
+            return None;
+        }
+
+        let mut maxlen = filter.maxlen;
+        if roa.maxlen != 0 {
+            if (roa.maxlen < maxlen) && (roa.maxlen > filter.minlen) {
+                maxlen = roa.maxlen;
+            }
+                // maxlen = std::cmp::max(std::cmp::min(maxlen, roa.maxlen), filter.minlen);
+        }
+
+        return Some(ROA {
             route: roa.route,
             origins: roa.origins,
-            maxlen: std::cmp::min(std::cmp::max(filter.minlen, roa.maxlen), filter.maxlen),
-        }
+            maxlen: maxlen,
+        });
     }).collect();
     // roas
 }