From owner-freebsd-questions Fri Dec 15 20: 6: 3 2000 From owner-freebsd-questions@FreeBSD.ORG Fri Dec 15 20:06:01 2000 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from grumpy.dyndns.org (user-24-214-56-157.knology.net [24.214.56.157]) by hub.freebsd.org (Postfix) with ESMTP id DC11437B400 for ; Fri, 15 Dec 2000 20:06:00 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by grumpy.dyndns.org (8.11.1/8.11.1) with ESMTP id eBG44v454729; Fri, 15 Dec 2000 22:04:57 -0600 (CST) (envelope-from dkelly@grumpy.dyndns.org) Message-Id: <200012160404.eBG44v454729@grumpy.dyndns.org> X-Mailer: exmh version 2.2 06/23/2000 with nmh-1.0.4 To: "Kevin Oberman" Cc: freebsd-questions@FreeBSD.ORG From: David Kelly Subject: Re: use of 1500 octet pings? In-reply-to: Message from "Kevin Oberman" of "Fri, 15 Dec 2000 11:14:16 PST." <200012151914.eBFJEGJ19767@ptavv.es.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Fri, 15 Dec 2000 22:04:57 -0600 Sender: dkelly@grumpy.dyndns.org Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG "Kevin Oberman" writes: > > Date: Wed, 13 Dec 2000 17:07:41 -0600 > > From: David Kelly > > Sender: owner-freebsd-questions@FreeBSD.ORG > > > > Watching reject messages on firewalls lately I've seen ICMP ECHO > > requests from web sites somebody is visiting, trying to packets of > > echo 1500 octets off us. What the heck are they trying to do? I can't > > guess an honest excuse for websites to ping visitors. And with such > > large packets. > > PMTU discovery? They may well be sending larger pings, but they don't > get to you. 1500 octets is probably the largest packet that can make > it to you without fragmentation. I don't know what they are doing but watch what happens when you try http://www.nga.gov/. Forcing MTU discovery with large pings on first access to a web site doesn't seem right. HP has sites which do the same thing. -- David Kelly N4HHE, dkelly@hiwaay.net ===================================================================== The human mind ordinarily operates at only ten percent of its capacity -- the rest is overhead for the operating system. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message