From owner-freebsd-questions@FreeBSD.ORG Sat Feb 12 16:56:53 2005 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 790AD16A4CE for ; Sat, 12 Feb 2005 16:56:53 +0000 (GMT) Received: from prosporo.hedron.org (hedron.org [66.11.182.60]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2169143D55 for ; Sat, 12 Feb 2005 16:56:53 +0000 (GMT) (envelope-from ean@hedron.org) Received: from localhost.hedron.org (localhost.hedron.org [127.0.0.1]) by prosporo.hedron.org (Postfix) with ESMTP id 80A59C0C5; Sat, 12 Feb 2005 11:57:06 -0500 (EST) From: Ean Kingston To: freebsd-questions@freebsd.org Date: Sat, 12 Feb 2005 11:57:05 -0500 User-Agent: KMail/1.7.1 References: <20050212165032.1637.qmail@web52003.mail.yahoo.com> In-Reply-To: <20050212165032.1637.qmail@web52003.mail.yahoo.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200502121157.05950.ean@hedron.org> cc: ann kok Subject: Re: ping question X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 12 Feb 2005 16:56:53 -0000 On February 12, 2005 11:50 am, ann kok wrote: > Hi all > > I ping from redhat to cisco router and freebsd router > but I don't understand ttl (time to live) ttl is 'time-to-live' it is a counter. Every router that the ping packet goes through subtracts 1 from the ttl value. When it reaches 0 (zero), the router that got the zero replies with a 'ttl exceeded message'. If the ping packet reaches it's destination before the ttl goes to zero, it replies with a 'ping reply'. This helps with diagnosis of network configuration issues. > Cisco router has ttl=251 and freebsd router has 58 > Does it set by the router itself? > Can I change it in freebsd? You control the ttl value from the place you send the ping from (in your description the RedHat system). When using ping from FreeBSD the -m parameter is used to set the initial value. I believe the initial value can be anything from 0 to 255. The default varies from system to system but the most common is 255. > > Thank you > [cut sample ping output] -- Ean Kingston E-Mail: ean AT hedron DOT org URL: http://www.hedron.org/