diff --git a/kike.c b/kike.c
index d66b012..5d0b1e5 100644
--- a/kike.c
+++ b/kike.c
@@ -2890,7 +2890,11 @@ irc_initialize_server_name (struct server_context *ctx, struct error **e)
 	}
 	else
 	{
-		char hostname[HOST_NAME_MAX];
+		long host_name_max = sysconf (_SC_HOST_NAME_MAX);
+		if (host_name_max <= 0)
+			host_name_max = _POSIX_HOST_NAME_MAX;
+
+		char hostname[host_name_max + 1];
 		if (gethostname (hostname, sizeof hostname))
 		{
 			error_set (e, "%s: %s",