Date: Tue, 14 May 2002 22:10:03 -0700 (PDT) From: "Crist J. Clark" <crist.clark@attbi.com> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/37602: netstat -i -b does not count outgoing packets for ip aliases Message-ID: <200205150510.g4F5A3g51656@freefall.freebsd.org>
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The following reply was made to PR bin/37602; it has been noted by GNATS.
From: "Crist J. Clark" <crist.clark@attbi.com>
To: james brown <jbsd@syndicate.net>
Cc: FreeBSD-gnats-submit@FreeBSD.ORG
Subject: Re: bin/37602: netstat -i -b does not count outgoing packets for ip aliases
Date: Tue, 14 May 2002 15:48:25 -0700
On Mon, May 13, 2002 at 04:45:04PM -0700, james brown wrote:
>
> > It doesn't make a lot of sense to track outgoing packets by source IP
> > address on an interface. The destination IP address determines which
>
> i think in our situation it does make sense. here is our setup:
>
> - a single network interface.
>
> - multiple ip address aliases on that interface.
>
> - multiple http and ftp daemons bound to those ip addresses.
>
> we want to measure the network traffic for each ip address using
> netstat -i -b in order to get statistics on how much traffic is moving
> in and out of these daemons.
But as you've found, you're not going to get it with netstat(1). That
information simply isn't tracked. Figuring out what alias address a
packet might be "leaving" simply isn't required in the IP output code,
so it is not convenient to track it (since it is a bunch of extra code
to run for every packet). And as I mentioned, in the case where you
have multiple interfaces, trying to track it would be confusing.
> > If you are playing with ipfw(8) accounting, you can see this by adding
> > rules like,
>
> i am aware that we can count bytes using ipfw accounting but this only
> produces the total in/out combined. we were hoping to use netstat
> because it displays in and out separately.
You can make ipfw(8) track in and out separately. In fact, I really
don't see how you could get it to track in and out combined,
pass ip from <alias> to any out
pass ip from any to <alias> in
> the bottom line is netstat -i -b does not appear to be working properly
> for ip aliases, this is why i submitted the gnats report.
The netstat(1) utility is working fine. It's just dumping the
counters in various in-kernel data structures. The fact is, the data
you desire is simply not and never has been tracked in the BSD stack.
Feel free to take a look in sys/netinet/ip_output.c and see if you can
find a place to do the accounting without creating too much additional
overhead.
--
Crist J. Clark | cjclark@alum.mit.edu
| cjclark@jhu.edu
http://people.freebsd.org/~cjc/ | cjc@freebsd.org
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