diff --git a/p2p/peer_error.go b/p2p/peer_error.go
index ab61bfef0..393cc86b0 100644
--- a/p2p/peer_error.go
+++ b/p2p/peer_error.go
@@ -89,7 +89,7 @@ var discReasonToString = [...]string{
 }
 
 func (d DiscReason) String() string {
-	if len(discReasonToString) < int(d) {
+	if len(discReasonToString) <= int(d) {
 		return fmt.Sprintf("unknown disconnect reason %d", d)
 	}
 	return discReasonToString[d]