diff --git a/src/server/server.c b/src/server/server.c
index 9e63f74f4..8e641176a 100644
--- a/src/server/server.c
+++ b/src/server/server.c
@@ -562,7 +562,7 @@ int server_loop(struct command_context *command_context)
 				struct connection *c;
 
 				for (c = service->connections; c; ) {
-					if ((FD_ISSET(c->fd, &read_fds)) || c->input_pending) {
+					if ((c->fd >= 0 && FD_ISSET(c->fd, &read_fds)) || c->input_pending) {
 						retval = service->input(c);
 						if (retval != ERROR_OK) {
 							struct connection *next = c->next;