Transcript Sess_09 - Vin Costa`s Wiki

Session 9
Networking & Operating Systems
(part 2)
Fall 2011
Nassau Community College
ITE153 – Operating Systems
1
Networking & Operating
Systems
IPv6, OSI, Standards
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IPv6
● 1995 – RFC 1752 IPng
● 1998 – RFC 2460 IPv6
● Functional enhancements for a mix of data
streams (graphic and video)
● Driving force was address depletion
128-bit addresses
● Started in Solaris 2.8, Windows 2000
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ITE153 – Operating Systems
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IPv6 Packet w/Extension Headers
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ITE153 – Operating Systems
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OSI Layers
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ITE153 – Operating Systems
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OSI Environment
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ITE153 – Operating Systems
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Internet Standards and RFCs
● Internet Architecture Board (IAB)
- overall architecture
● Internet Engineering Task Force (IETF)
- engineering and development
● Internet Engineering Steering Group (IESG)
- manages the IETF and standards process
Fall 2011
Nassau Community College ITE153
– Operating Systems
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Request For Comments (RFC)
● RFCs are the working notes of the Internet
research and development community
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ITE153 – Operating Systems
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Standardization Process
●
●
●
●
●
Stable and well understood
Technically competent
Substantial operational experience
Significant public support
Useful in some or all parts of Internet
Key difference from ISO: operational experience
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ITE153 – Operating Systems
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RFC Publication Process
IETF
< 6 months
Internet
draft
IESG
> 6 months
Proposed
Experimental
Informational
standard
two independent
implementations
> 4 months
Draft
standard
Internet
standard
Historic
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Hands-on
Exercises
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What Is My IPAddress?
● You can find it for your interface using any
one of the commands:
ifconfig
ifconfig –a
ifconfig [interface]
netstat -i
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Here’s How I Bring the Interface Up
● Assume my interface is eth0, then use:
ifconfig eth0
● You will get:
eth0
Link encap:Ethernet HWaddr 00:30:1b:48:dc:3d
inet addr:192.168.0.100 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::230:1bff:fe48:dc3d/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1494920 errors:0 dropped:0 overruns:0 frame:0
TX packets:1219954 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1621598747 (1.6 GB) TX bytes:302524693 (302.5 MB)
Interrupt:17
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Here’s An Example:
● Assume my interface is eth0, then use:
ifconfig eth0 192.168.0.100
netmask 255.255.255.0 broadcast
192.168.0.255 up
● You probably don’t have permission to do
this 
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How Do I Know I Can Get Out On the
Network?
● We use the ping command
● It is very simple. It sends an
ICMP_ECHO_REQUEST packet to a target
host and waits for an answer
● It is one of the workhorses of network
debugging
● Here’ an example:
ping www.google.edu
● Some sites disable ping responses!
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Ping Sample
papacosta@papacosta-desktop:~$ ping www.google.com
PING www.l.google.com (74.125.226.208) 56(84) bytes of data.
64 bytes from lga15s28-in-f16.1e100.net (74.125.226.208): icmp_req=1 ttl=55 time=9.82 ms
64 bytes from lga15s28-in-f16.1e100.net (74.125.226.208): icmp_req=2 ttl=55 time=9.86 ms
64 bytes from lga15s28-in-f16.1e100.net (74.125.226.208): icmp_req=3 ttl=55 time=10.7 ms
64 bytes from lga15s28-in-f16.1e100.net (74.125.226.208): icmp_req=4 ttl=55 time=13.6 ms
^C
--- www.l.google.com ping statistics --4 packets transmitted, 4 received, 0% packet loss, time 3004ms
rtt min/avg/max/mdev = 9.821/11.013/13.607/1.545 ms
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netstat Command to Check Routing
● The netstat command provides a wealth
of information about the state of your
computer's networking software, including
interface statistics, routing information, and
connection tables
● Here are some typical commands to
 monitor connection status: netstat -a
 see interface status: netstat -i
 display routing table: netstat -r –n
 View operational stats: netstat -s
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nslookup Command
● The nslookup command is a very old
command (used in both UNIX and
DOS/Windows) to query the DNS
database
● Here is an example:
nslookup www.google.com
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dig Command
● The dig command is in functionality, but has
more sensible defaults, provides more info, and
has a nicer user interface
● Here are a few examples:
dig www.google.com
dig google.com any
dig google.com mx
dig google.com ns
dig -x 216.239.34.10
● This can get even more involved:
dig +nocmd google.com any +multiline
+noall +answer
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Important URLs
● Internetworking Technology Handbook – Cisco’s excellent
and extensive Wiki on networking technology
● http://www.rfc-editor.org/rfcsearch.html - great place to
search RFCs
● Dig How To Guide - an excellent explanation, with lots of
examples, on how to effectively use the dig command line
tool
● Linux: Check Network Connection Command – good
explanation of the ss and netstat commands
● IP Chicken – this displays your “public” IP address
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– Operating Systems
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Homework
 Review the Slides
 Do the Exercise: ipconfig, ping, netstat,
nslookup, & dig
 Complete the Take-Home Exam
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