diff --git a/tmate-ssh-server.c b/tmate-ssh-server.c
index 7f800b73..25c7878c 100644
--- a/tmate-ssh-server.c
+++ b/tmate-ssh-server.c
@@ -210,7 +210,7 @@ static void handle_sigalrm(__unused int sig)
 static void client_bootstrap(struct tmate_session *_session)
 {
 	struct tmate_ssh_client *client = &_session->ssh_client;
-	int grace_period = TMATE_SSH_GRACE_PERIOD;
+	long grace_period = TMATE_SSH_GRACE_PERIOD;
 	ssh_event mainloop;
 	ssh_session session = client->session;