From owner-freebsd-net@FreeBSD.ORG Sat May 17 08:58:55 2003 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 6E79237B401 for ; Sat, 17 May 2003 08:58:55 -0700 (PDT) Received: from lariat.org (lariat.org [63.229.157.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id B91F843FDD for ; Sat, 17 May 2003 08:58:54 -0700 (PDT) (envelope-from brett@lariat.org) Received: (from root@localhost) by lariat.org (8.9.3/8.9.3) id JAA16811 for net@freebsd.org; Sat, 17 May 2003 09:58:53 -0600 (MDT) Date: Sat, 17 May 2003 09:58:53 -0600 (MDT) From: Brett Glass Message-Id: <200305171558.JAA16811@lariat.org> To: net@freebsd.org Subject: Ping results are sometimes wrong X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 17 May 2003 15:58:55 -0000 Just noticed that FreeBSD's ping program was giving me inaccurate stats when pinging hosts on the local subnet (but not on remote subnets). Some investigation has revealed why: the delay for the very first ping includes the time (if any) it takes to use ARP to discover the MAC address of the target. This introduces an outlying data point that messes up the stats; it makes them look as if there are extra delays or congestion on the network. Perhaps the program should make sure that the MAC address of the target (if it's on the local network) has been resolved before starting to ping? --Brett Glass