Session 9 Networking & Operating Systems (part 2)

1. Nassau Community College ITE153 – Operating Systems Session 9Networking & Operating Systems(part 2)

2. IPv6, OSI, Standards Nassau Community College ITE153 – Operating Systems Networking & Operating Systems

3. IPv6 Nassau Community College ITE153 – Operating Systems • 1995 – RFC 1752 IPng • 1998 – RFC 2460 IPv6 • Functional enhancements for a mix of data streams (graphic and video) • Driving force was address depletion128-bit addresses • Started in Solaris 2.8, Windows 2000

4. IPv6 Packet w/Extension Headers Nassau Community College ITE153 – Operating Systems

5. OSI Layers Nassau Community College ITE153 – Operating Systems

6. OSI Environment Nassau Community College ITE153 – Operating Systems

7. Internet Standards and RFCs Nassau Community College ITE153 – Operating Systems • 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

8. Request For Comments (RFC) Nassau Community College ITE153 – Operating Systems • RFCs are the working notes of the Internet research and development community

9. Standardization Process Nassau Community College ITE153 – Operating Systems • 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

10. RFC Publication Process Nassau Community College ITE153 – Operating Systems

11. Hands-onExercises Nassau Community College ITE153 – Operating Systems

12. What Is My IPAddress? Nassau Community College ITE153 – Operating Systems • You can find it for your interface using any one of the commands:ifconfigifconfig –aifconfig [interface]netstat -i

13. Here’s How I Bring the Interface Up Nassau Community College ITE153 – Operating Systems • Assume my interface is eth0, then use:ifconfig eth0 • You will get: eth0 Link encap:EthernetHWaddr00:30:1b: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

14. Here’s An Example: Nassau Community College ITE153 – Operating Systems • 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 

15. How Do I Know I Can Get Out On the Network? Nassau Community College ITE153 – Operating Systems • 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!

16. Ping Sample Nassau Community College ITE153 – Operating Systems • 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

17. netstat Command to Check Routing Nassau Community College ITE153 – Operating Systems • 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

18. nslookup Command Nassau Community College ITE153 – Operating Systems • 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

19. dig Command Nassau Community College ITE153 – Operating Systems • 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.comdig google.com anydig google.com mxdig google.com nsdig -x 216.239.34.10 • This can get even more involved:dig +nocmd google.com any +multiline +noall +answer

20. Important URLs Nassau Community College ITE153 – Operating Systems • 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

21. Homework Nassau Community College ITE153 – Operating Systems • Review the Slides • Do the Exercise: ipconfig, ping, netstat, nslookup, & dig • Complete the Take-Home Exam