Subtitles of the Movie

In this video let's examine some of the client tools associated with DHCP, DNS and specialized routing. Once configured its easy to start a DHCP client, just run the DH clack command. Sometimes you may get a message to the effect that the DHCP client is already running but you're wanting to try again say to get a new IP address. To do so we'll first have to kill the current DHCP client process. We discussed how you can kill a process in a different movie. So let's just do that here, to do so you need to find the process identifier associated with the currently running DH client command and there it is. So we apply the kill command, in this case to process identifier number 5564 and now we run the DH client command again. If you have more than one network card you can apply it to that network card such as ETH zero. And there it is, the DH client command at work. It sends a broadcast, a general broadcast for a DHCP server, it finds one, it gets an offer, it confirms the request, it gets an acknowledgment, and an IP address ready for use on the first ether net card, and there it is. Next let's look at DNS clients. It's a enabled by default courtesy of the ETC host dot com file. What this means is when you run something like the ping command or search the Internet for something like www dot VTC dot com, the first thing the system does is look through the ETC slash host file. If it doesn't find it there it then searches through DNS files in the ETC slash resolve dot com configuration file. BIND is the Berkeley Internet name daemon which is the most popular DNS server associated with Linux. It searches throughout the database, it finds the IP address and it goes through the route and there the ping is successful. Finally specialized routing commands are specified in the route file that's associated with the network device. We're looking in this particular file here. We have a specialized route through a special gateway with a net mask and this is my network address and I've set this up so I can access my other network with this network address through my desktop computer which has a second ether net card on this network address, but it's not currently active. If I want to add this route I use the route command to add the network address with the gateway address specified, and there it is. Thank you and on to the next video.