Date: Fri, 23 Jun 1995 22:01:57 -0700 (PDT) From: "Rodney W. Grimes" <rgrimes@gndrsh.aac.dev.com> To: evanc@synapse.net Cc: hackers@freefall.cdrom.com Subject: Re: Network Usage Stats Message-ID: <199506240501.WAA12272@gndrsh.aac.dev.com> In-Reply-To: <199506240057.UAA28543@sentinel.synapse.net> from "Evan Champion" at Jun 23, 95 08:57:30 pm
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> > I am looking for a non-intrusive, hopefully low-CPU usage network > usage monitor that can tell me something about how much the network(s) > going in to a FreeBSD router is being used. > > Is there such a beast? Well, it is not quite what you want, but your FreeBSD router has it built in. It is kernel pseudo-device bpfilter: # The `bpfilter' pseudo-device enables the Berkeley Packet Filter. Be # aware of the legal and administrative consequences of enabling this # option. The number of devices determines the maximum number of # simultaneous BPF clients programs runnable. pseudo-device bpfilter 4 #Berkeley packet filter It is intrusive if run on the router itself as that will place additional load on it. But, if you take another FreeBSD box and hang it on the net to be watched it makes a reasonable very low cost sniffer (nothing like a real one mind you, but it gets the job done for me). See man tcpdump and man bpf for how to dump and filter packets once you have configured this into your kernel. -- Rod Grimes rgrimes@gndrsh.aac.dev.com Accurate Automation Company Reliable computers for FreeBSD
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