diff --git a/usr.sbin/routed/inet.c b/usr.sbin/routed/inet.c
index 925472c287b4..9b1c9fdda680 100644
--- a/usr.sbin/routed/inet.c
+++ b/usr.sbin/routed/inet.c
@@ -143,13 +143,13 @@ inet_maskof(inaddr)
 	} else if (IN_CLASSA(i)) {
 		mask = IN_CLASSA_NET;
 	} else if (IN_CLASSB(i)) {
-		mask = i & IN_CLASSB_NET;
+		mask = IN_CLASSB_NET;
 	} else
-		mask = i & IN_CLASSC_NET;
+		mask = IN_CLASSC_NET;
 
 	/*
-	 * Check whether network is a subnet;
-	 * if so, use the modified interpretation of `host'.
+	 * Check whether network is subnetted;
+	 * if so, use the subnet's netmask.
 	 */
 	for (ifp = ifnet; ifp; ifp = ifp->int_next)
 		if ((ifp->int_netmask & i) == ifp->int_net)