From owner-freebsd-questions@FreeBSD.ORG Wed Jun 13 19:21:00 2007 Return-Path: X-Original-To: questions@freebsd.org Delivered-To: freebsd-questions@FreeBSD.ORG Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 5C0FB16A400 for ; Wed, 13 Jun 2007 19:21:00 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from mail-out3.apple.com (mail-out3.apple.com [17.254.13.22]) by mx1.freebsd.org (Postfix) with ESMTP id 45E9A13C4B8 for ; Wed, 13 Jun 2007 19:21:00 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from relay5.apple.com (relay5.apple.com [17.128.113.35]) by mail-out3.apple.com (Postfix) with ESMTP id 5C4BE8C02AE; Wed, 13 Jun 2007 12:19:52 -0700 (PDT) Received: from relay5.apple.com (unknown [127.0.0.1]) by relay5.apple.com (Symantec Mail Security) with ESMTP id 1ECD829C003; Wed, 13 Jun 2007 12:21:00 -0700 (PDT) X-AuditID: 11807123-a0022bb000000a23-3c-4670439c1cd6 Received: from [17.214.13.96] (cswiger1.apple.com [17.214.13.96]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by relay5.apple.com (Apple SCV relay) with ESMTP id 1131D30400B; Wed, 13 Jun 2007 12:21:00 -0700 (PDT) In-Reply-To: <17838240D9A5544AAA5FF95F8D52031602171721@ad-exh01.adhost.lan> References: <17838240D9A5544AAA5FF95F8D52031602171721@ad-exh01.adhost.lan> Mime-Version: 1.0 (Apple Message framework v752.2) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: <68F60D1E-2344-4140-B8E1-056947452C1F@mac.com> Content-Transfer-Encoding: 7bit From: Chuck Swiger Date: Wed, 13 Jun 2007 12:20:59 -0700 To: Michael K. Smith - Adhost X-Mailer: Apple Mail (2.752.2) X-Brightmail-Tracker: AAAAAA== Cc: questions@freebsd.org Subject: Re: Ethernet Card Limitations to Number of Connections? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 13 Jun 2007 19:21:00 -0000 On Jun 13, 2007, at 10:14 AM, Michael K. Smith - Adhost wrote: > Are there any physical limitations to the number of connections > (TCP/UDP) that are determined by the physical interface itself? Sure. Divide the interface speed by the size of the smallest packets one can send including ethernet preamble, all headers, and the minimal gap between frames. There's a PDF here with all of the details: ftp://ftp.cs.princeton.edu/techreports/2002/645.pdf ...but for 100Mbs full-duplex, you can send up to ~150 Kpps of minimum-size packets, or ~8 Kpps for max-sized packets. > We have a PF load-balancing solution in place in front of a large > number of mail > servers and we're considering using the same boxes to front our Name > Server/Name Resolvers. I'm concerned that the single uplink port > on the > PF box will be overloaded with the number of connections. > > Any insights would be greatly appreciated. One hopes that your "large number of mail servers" are only sending email to people who have actually opted in and wish to receive such email...? -- -Chuck