diff --git a/types/ipproto/ipproto.go b/types/ipproto/ipproto.go
index a08985b3a..946ac12cd 100644
--- a/types/ipproto/ipproto.go
+++ b/types/ipproto/ipproto.go
@@ -109,7 +109,7 @@ func (p Proto) String() string {
 // https://www.iana.org/assignments/protocol-numbers/protocol-numbers.xhtml
 // unless otherwise noted.
 var (
-	// preferredNames is the set of protocol names that re produced by
+	// preferredNames is the set of protocol names that are produced by
 	// MarshalText, and are the preferred representation.
 	preferredNames = map[Proto]string{
 		51:     "ah",