diff --git a/pkg/decoders/prefix.go b/pkg/decoders/prefix.go
index 08da700..02e0917 100644
--- a/pkg/decoders/prefix.go
+++ b/pkg/decoders/prefix.go
@@ -27,6 +27,11 @@ func MaybePrefix(s string) bool {
 		return false
 	}
 
+	// Must contain at least one dot or colon
+	if !strings.Contains(s, ":") && !strings.Contains(s, ".") {
+		return false
+	}
+
 	// Test using regex
 	matches := ReMatchIPPrefix.FindAllStringIndex(s, -1)
 	if len(matches) == 1 {
diff --git a/pkg/decoders/prefix_test.go b/pkg/decoders/prefix_test.go
index f891bc7..6d1fbcf 100644
--- a/pkg/decoders/prefix_test.go
+++ b/pkg/decoders/prefix_test.go
@@ -12,9 +12,11 @@ func TestMaybePrefix(t *testing.T) {
 		{"10.0.0", true},
 		{"23.42.11.42/23", true},
 		{"fa42:2342::/32", true},
-		{"200", true},
+		{"1.", true},
+		{"200", false},
+		{"200.", true},
 		{"2001:", true},
-		{"A", true},
+		{"A", false},
 		{"A b", false},
 		{"23 Foo", false},
 		{"Nordfoo", false},