diff --git a/filter/trie.c b/filter/trie.c
index 565ae82f..6477fbbf 100644
--- a/filter/trie.c
+++ b/filter/trie.c
@@ -277,8 +277,21 @@ trie_node_format(struct f_trie_node *t, buffer *buf)
   if (t == NULL)
     return;
 
-  if (ipa_nonzero(t->accept))
-    buffer_print(buf, "%I/%d{%I}, ", t->addr, t->plen, t->accept);
+  ip_addr amask = t->accept;
+  while (ipa_nonzero(amask))
+    {
+      int top, bottom;
+      ip_addr cmask = ipa_bitrange(amask, &top, &bottom);
+
+      if ((t->plen == top) && (t->plen == bottom-1))
+	buffer_print(buf, "%I/%d, ", t->addr, t->plen);
+      else if ((t->plen == top) && (bottom-1 == MAX_PREFIX_LENGTH))
+	buffer_print(buf, "%I/%d+, ", t->addr, t->plen);
+      else
+	buffer_print(buf, "%I/%d{%d,%d}, ", t->addr, t->plen, top, bottom-1);
+
+      amask = ipa_xor(amask, cmask);
+    }
 
   trie_node_format(t->c[0], buf);
   trie_node_format(t->c[1], buf);
diff --git a/lib/bitops.c b/lib/bitops.c
index 81586e87..9e05be57 100644
--- a/lib/bitops.c
+++ b/lib/bitops.c
@@ -68,3 +68,27 @@ u32_log2(u32 v)
   return r;
 }
 
+/**
+ * u32_bitrange - find a contiguos series of 1's.
+ * @v: number
+ * @tp: pointer to top index (first 1: <31,0>)
+ * @bp: pointer to bottom index (first 0: <30,-1>)
+ * 
+ * This functions finds the most significant contiguous series of 1's and returns it.
+ * If the pointers are set, the indices are also written there.
+ */
+u32
+u32_bitrange(u32 v, int *tp, int *bp)
+{
+						/* Example:		0x07ffe030 */
+  int ti = u32_log2(v);				/* Get first 1's index: 26 */
+  u32 t = (1 << (ti + 1)) - 1;			/* Get 1's mask:	0x07ffffff */
+  u32 r = t ^ v;				/* Unmask the 1's:	0x00001fcf */
+  int bi = (v & (v+1)) ? (int)u32_log2(r) : -1;	/* Get first 1's index:	12 */
+  u32 b = (1 << (bi + 1)) - 1;			/* Get the mask:	0x00001fff */
+  if (tp)
+    *tp = ti;
+  if (bp)
+    *bp = bi;
+  return t ^ b;					/* Return the bitrange: 0x07ffe000 */
+}
diff --git a/lib/bitops.h b/lib/bitops.h
index ce13732a..ae763289 100644
--- a/lib/bitops.h
+++ b/lib/bitops.h
@@ -22,6 +22,7 @@ u32 u32_mkmask(uint n);
 int u32_masklen(u32 x);
 
 u32 u32_log2(u32 v);
+u32 u32_bitrange(u32 v, int *top, int *bottom);
 
 static inline u32 u32_hash(u32 v) { return v * 2902958171u; }
 
diff --git a/lib/ip.h b/lib/ip.h
index d876a707..aac55572 100644
--- a/lib/ip.h
+++ b/lib/ip.h
@@ -326,6 +326,15 @@ static inline ip4_addr ip4_mkmask(uint n)
 static inline int ip4_masklen(ip4_addr a)
 { return u32_masklen(_I(a)); }
 
+static inline ip4_addr ip4_bitrange(ip4_addr a, int *tp, int *bp)
+{
+  int t, b;
+  a = u32_bitrange(a, &t, &b);
+  if (tp) *tp = 32-t;
+  if (bp) *bp = 32-b;
+  return a;
+}
+
 ip6_addr ip6_mkmask(uint n);
 int ip6_masklen(ip6_addr *a);
 
@@ -373,6 +382,7 @@ ip4_addr ip4_class_mask(ip4_addr ad);
 #else
 #define ipa_mkmask(x) ip4_mkmask(x)
 #define ipa_masklen(x) ip4_masklen(x)
+#define ipa_bitrange(x,tp,bp) ip4_bitrange(x,tp,bp)
 #define ipa_pxlen(x,y) ip4_pxlen(x,y)
 #define ipa_getbit(x,n) ip4_getbit(x,n)
 #define ipa_opposite_m1(x) ip4_opposite_m1(x)