diff --git a/CHANGES b/CHANGES
index 2c7f387cbe..ec7d2da7e7 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,5 @@
+2689.	[bug]		Correctly handle snprintf result. [RT #20306]
+
 2688.	[bug]		Use INTERFACE_F_POINTTOPOINT, not IFF_POINTOPOINT,
 			to decide to fetch the destination address. [RT #20305]
 
diff --git a/lib/dns/dst_api.c b/lib/dns/dst_api.c
index 022caeba12..84aa747d7c 100644
--- a/lib/dns/dst_api.c
+++ b/lib/dns/dst_api.c
@@ -18,7 +18,7 @@
 
 /*
  * Principal Author: Brian Wellington
- * $Id: dst_api.c,v 1.1.6.13 2009/07/29 23:56:27 each Exp $
+ * $Id: dst_api.c,v 1.1.6.14 2009/09/24 22:25:30 marka Exp $
  */
 
 /*! \file */
@@ -1223,6 +1223,8 @@ addsuffix(char *filename, unsigned int len, const char *ofilename,
 
 	n = snprintf(filename, len, "%.*s%s", olen, ofilename, suffix);
 	if (n < 0)
+		return (ISC_R_FAILURE);
+	if (n >= len)
 		return (ISC_R_NOSPACE);
 	return (ISC_R_SUCCESS);
 }