netstat output - diff between 'link' and 'inet' counters
nkinkade at ub.edu.bz
Thu May 20 13:28:08 PDT 2004
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?
> 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:
> % netstat -I de0
> Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll
> de0 1500 <Link#1> 00:40:05:a5:8d:b7 149504 0 111734 4 0
> de0 1500 184.108.40.206/2 smtp 70771 - 120940 - -
> de0 1500 fe80:1::240 fe80:1::240:5ff:f 0 - 3 - -
> de0 1500 220.127.116.11/3 arbitrary 371042 - 301860 - -
> Now, link#1 corresponds to my local network (from 'netstat -r'):
> 18.104.22.168/29 link#1 UC 2 0 de0
> So the Ipkts count is for all the packets passing that interface with
> a destination address matching the 22.214.171.124/29 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 126.96.36.199
> The other three entries are for the specific addresses assigned to
> that interface -- I have the principal IP number on the interface as
> 188.8.131.52, and a jail using 184.108.40.206, plus the automatically
> assigned IPv6 link-local address. (IPv6 traffic mostly goes via a
> gif(4) tunnel which acts like a different interface.
Yes, I was referring to netstat's output with the '-i' switch. The
information you provided is exactly what I was looking for.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Size: 189 bytes
Desc: not available
Url : http://lists.freebsd.org/pipermail/freebsd-questions/attachments/20040520/66c21fbf/attachment.bin
More information about the freebsd-questions