diff --git a/Makefile b/Makefile
index 8e04613..42c4212 100644
--- a/Makefile
+++ b/Makefile
@@ -78,6 +78,7 @@ fuzz:
 	go test -fuzz . -parallel 1 -fuzztime 5m ./junk
 	go test -fuzz FuzzParseRecord -fuzztime 5m ./mtasts
 	go test -fuzz FuzzParsePolicy -fuzztime 5m ./mtasts
+	go test -fuzz . -fuzztime 5m ./smtp
 	go test -fuzz . -parallel 1 -fuzztime 5m ./smtpserver
 	go test -fuzz . -fuzztime 5m ./spf
 	go test -fuzz FuzzParseRecord -fuzztime 5m ./tlsrpt