Traceroute demonstration Skills: : use traceroute and query the whois database Concepts: router hops, whois database We will use a network utility program called traceroute, to see which routers a packet passes through in moving across the Internet from one computer to another. We will also see how to query the whois database and review prefixes for small quantities. This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.

Where does this topic fit? Internet concepts Applications Technology (communication) Implications Internet skills Application development Content creation User skills This presentation deals with communication technology.

Traceroute We saw that routers forward packets from network to network as they move across the Internet. Traceroute lets us see the routers at each hop and we can often identify the network they are associated with.

How many hops? How many hops? How many hops do you think there are between Los Angeles and northern California? Between Los Angeles and Santiago Chile?

Traceroute demonstration Start > Run Traceroute demonstration – check routes to Google and the University of Chile. Note that the Windows traceroute client is called tracert. Note that some networks block traceroute, so you see “request timed out.”

Night = Day? Home = School? Same route? Why does the route vary depending upon when and where you run the test?

Whois OrgName:       California State University OrgId:           CSU-13 Address:         1000 East Victoria St City:            Carson StateProv:      CA PostalCode:    90502 Country:         US RegDate:         1991-11-08 Updated:         2003-05-27 Traceroute gives the IP addresses of the routers between two hosts. You can often identify the organization that owns the router by querying a whois database. There are many whois lookup services on the Web, like the one shown here, Dnstools.com. http://www.dnstools.com

For more on this topic, see this teaching module.