Date: Thu, 20 May 2004 14:27:57 -0600 From: Nathan Kinkade <nkinkade@ub.edu.bz> To: freebsd-questions@freebsd.org Subject: Re: netstat output - diff between 'link' and 'inet' counters Message-ID: <20040520202757.GF3534@gentoo-npk.bmp.ub> In-Reply-To: <20040520190358.GA10740@happy-idiot-talk.infracaninophile.co.uk> References: <20040520172301.GB3534@gentoo-npk.bmp.ub> <20040520190358.GA10740@happy-idiot-talk.infracaninophile.co.uk>
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--2CKPe999o93Mtx0C Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, May 20, 2004 at 08:03:58PM +0100, Matthew Seaman wrote: > On Thu, May 20, 2004 at 11:23:01AM -0600, Nathan Kinkade wrote: > > I delved into trying to determine the cause of an unreasonably high > > number of Ierrs on a few FreeBSD routers we have setup on campus. While > > probing through the netstat output on the machines I realized that I > > don't understand the exact difference between the 'inet' and 'link' > > protocol families. Now, I understand the difference between IP and > > ethernet, but the byte and packet counts for 'inet' and 'link' don't > > seem to match what I would expect for those protocols, respectively. > > This tells me that the numbers being logged must differ from my > > expectations. Generally I notice that the 'inet' counts for an > > interface are a relatively small fraction of that for the 'link' > > counts for the same interface. However, on our main FreeBSD router that > > provides NAT and access to the internet the numbers are somewhat > > reversed, with 'inet' counts being much higher than the 'link' counts. > > Is there someone who can explain to me exactly what packet and byte > > counts actually represent for the 'inet' and 'link' families? >=20 > I surmise that you're talking about the per-interface statistics as > reported by 'netstat -i' or 'netstat -I ifN' rather than any other set > of flags to netstat. Let's look at what I get on my system: >=20 > % netstat -I de0 > Name Mtu Network Address Ipkts Ierrs Opkts O= errs Coll > de0 1500 <Link#1> 00:40:05:a5:8d:b7 149504 0 111734 = 4 0 > de0 1500 81.2.69.216/2 smtp 70771 - 120940 = - - > de0 1500 fe80:1::240 fe80:1::240:5ff:f 0 - 3 = - - > de0 1500 81.2.69.219/3 arbitrary 371042 - 301860 = - - >=20 > Now, link#1 corresponds to my local network (from 'netstat -r'): >=20 > 81.2.69.216/29 link#1 UC 2 0 de0 >=20 > So the Ipkts count is for all the packets passing that interface with > a destination address matching the 81.2.69.216/29 network but not > including packets to one of the specific addresses on that > interface. That includes many packets for some unused addesses out of > my netblock[*] and also packets to the broadcast address 81.2.69.219 >=20 > The other three entries are for the specific addresses assigned to > that interface -- I have the principal IP number on the interface as > 81.2.69.218, and a jail using 81.2.69.219, plus the automatically > assigned IPv6 link-local address. (IPv6 traffic mostly goes via a > gif(4) tunnel which acts like a different interface. >=20 > Cheers, >=20 > Matthew Yes, I was referring to netstat's output with the '-i' switch. The information you provided is exactly what I was looking for. Thanks! Nathan --2CKPe999o93Mtx0C Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) iD8DBQFArRTNO0ZIEthSfkkRAvMmAKC2Z3Eln6upIM9if/85IbVVb5slLACg7Ut+ cqS8RdWzJ6PM0Y/RS/tTCQg= =I1or -----END PGP SIGNATURE----- --2CKPe999o93Mtx0C--
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