Ethereal-users: RE: [Ethereal-users] Could Ethereal monitor bad-packet COUNTS in linux?

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From: Alistair.McGlinchy@xxxxxxxxxxxxxxxxxxxxx
Date: Mon, 24 Feb 2003 20:12:09 -0000
Peter,

> >Having said that, Ethereal does offer some very useful 
> display filters 
> >terms such as ip.checksum_bad, ip.fragment.error, tcp.segment.error 
> >etc.
> 
> ... if only our NICs would provide any data in those terms! 
> Doesn't seem to happen for us.

They almost certainly do. There's a plethora of information available at the
MAC, IP and UDP/ICMP/TCP layer via SNMP within the standard MIB II.  Note
the similarities between these two commands, the good bit is that I could
just as easily have run the snmpwalk from any machine in the network:

[root@gbhitopswksu531 alistair]# netstat -s --udp
Udp:
    3313661 packets received
    17 packets to unknown port received.
    0 packet receive errors
    424720 packets sent
[root@gbhitopswksu531 alistair]# snmpwalk localhost public .1.3.6.1.2.1.7
udp.udpInDatagrams.0 = Counter32: 3314467
udp.udpNoPorts.0 = Counter32: 17
udp.udpInErrors.0 = Counter32: 0
udp.udpOutDatagrams.0 = Counter32: 424848
<snip>

As you're running Linux you will already have useful snmp commands available
to you. We windows users are not so lucky, but even Windows supports MIB II.
For tutorials etc check out http://net-snmp.sourceforge.net/. 

A wee bit of cut and paste from my Windows based MIB Browser shows the
following info ...

At the MAC, 
13: ifInDiscards - Counter32(65 - cntr32)
14: ifInErrors - Counter32(65 - cntr32)
15: ifInUnknownProtos - Counter32(65 - cntr32)
16: ifOutOctets - Counter32(65 - cntr32)
17: ifOutUcastPkts - Counter32(65 - cntr32)
18: ifOutNUcastPkts - Counter32(65 - cntr32)
19: ifOutDiscards - Counter32(65 - cntr32)
20: ifOutErrors - Counter32(65 - cntr32)
21: ifOutQLen - Gauge32(66 - gauge32)

IP ...
8: ipInDiscards.0 (counter) 0
9: ipInDelivers.0 (counter) 2974617
10: ipOutRequests.0 (counter) 1923851
11: ipOutDiscards.0 (counter) 2481
12: ipOutNoRoutes.0 (counter) 3593
13: ipReasmTimeout.0 (integer) 30
14: ipReasmReqds.0 (counter) 0

and TCP layer...
8: tcpEstabResets.0 (counter) 9
9: tcpCurrEstab.0 (gauge) 4
33: tcpInErrs.0 (counter) 0
34: tcpOutRsts.0 (counter) 13

HTH

Alistair


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