From owner-freebsd-net Sat Aug 8 08:52:41 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id IAA25225 for freebsd-net-outgoing; Sat, 8 Aug 1998 08:52:41 -0700 (PDT) (envelope-from owner-freebsd-net@FreeBSD.ORG) Received: from labinfo.iet.unipi.it (labinfo.iet.unipi.it [131.114.9.5]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id IAA25206; Sat, 8 Aug 1998 08:52:38 -0700 (PDT) (envelope-from luigi@labinfo.iet.unipi.it) Received: from localhost (luigi@localhost) by labinfo.iet.unipi.it (8.6.5/8.6.5) id QAA16403; Sat, 8 Aug 1998 16:02:17 +0200 From: Luigi Rizzo Message-Id: <199808081402.QAA16403@labinfo.iet.unipi.it> Subject: Re: Does this impose a high load on a system? To: andre.albsmeier@mchp.siemens.de (Andre Albsmeier) Date: Sat, 8 Aug 1998 16:02:17 +0200 (MET DST) Cc: freebsd-net@FreeBSD.ORG, freebsd-questions@FreeBSD.ORG In-Reply-To: <199808081532.RAA18920@internal> from "Andre Albsmeier" at Aug 8, 98 05:31:58 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > Hello, > > I am running a nice little program named arpwatch. It collects > information about new machines being attached to a network. > I do this because I can monitor if someone links a new > machine to our nets. > > For this operation, the network interface is put into promiscuous mode. > IIRC, this means that all packets are passed to the kernel and maybe > even all to the running program (arpwatch). I wonder if this causes > a high load on the machine since I think it might have to process it depends on how much data it copies from the packet up to user space. To see if there is really a performance problem you should probably try to flood the local network segment with a separate machine and see how much load this causes. If you are concerned about performance maybe you can hack the network driver to grab the info you need, store in a table, and access them via some separate interface. (i am thinking of a similar approach in an attempt to implement bridging in freebsd). cheers luigi -----------------------------+-------------------------------------- Luigi Rizzo | Dip. di Ingegneria dell'Informazione email: luigi@iet.unipi.it | Universita' di Pisa tel: +39-50-568533 | via Diotisalvi 2, 56126 PISA (Italy) fax: +39-50-568522 | http://www.iet.unipi.it/~luigi/ _____________________________|______________________________________ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message