diff --git a/dtls.c b/dtls.c
index 4c92a05..d864b26 100644
--- a/dtls.c
+++ b/dtls.c
@@ -534,6 +534,7 @@ static void cleanup_connection(struct server *server) {
         SSL_shutdown(server->ssl);
     if (server->sock >= 0)
         close(server->sock);
+    server->sock = -1;
     if (server->ssl)
         SSL_free(server->ssl);
     server->ssl = NULL;
diff --git a/tls.c b/tls.c
index 46088cc..104e63d 100644
--- a/tls.c
+++ b/tls.c
@@ -87,6 +87,7 @@ static void cleanup_connection(struct server *server) {
         SSL_shutdown(server->ssl);
     if (server->sock >= 0)
         close(server->sock);
+    server->sock = -1;
     if (server->ssl)
         SSL_free(server->ssl);
     server->ssl = NULL;