1z0-821 Oracle Solaris 11 System Administration – Administering a Physical Network

1. Exam Objectives

During this next session, we’re going to talk about administering a physical network for the OCA exam. You have one objective and several subojectives that cover networking. We’re going to go over a few of these during this session and in depth on all of them in the next few sessions. First of all, the exam wants us to be able to explain basic networking concepts. Now, one of the things I realize is that you probably all have some experience in administering other types of operating systems. So you probably have some experience administering networks to a certain degree. So what we’re not going to do is take you through a very basic networking course because it’s not practical. It would take an entire course to do it. And there are other courses that you could study to get that information. But we will go back and just explain a few basic networking principles and concepts just to refresh your memory and to explain how they apply to Solaris Eleven in particular.

Simply because Solaris Eleven does things sometimes a little bit differently and introduces some new processes, commands and different ways of doing things and administering networks into its system. So we’ll talk about some basic networking concepts, but we won’t go in depth. The other thing you need to keep in mind is most of the discussion we’ll have on networks for this course center around what goes on on the box itself, how it relates to the system, and administrating a single solaris system. You won’t see advanced topics such as turning the system into a DHCP server or a DNS server or a web server. But you will talk about or listen to me talk about rather, how to configure the system to use DNS as a client or DHCP as a service and use other types of services to communicate with other services on the network. So we’re really client centered during this discussion, not server centered. Keep that in mind. So the topics that we’re going to discuss are explaining basic networking concepts and we’ll talk about IP addressing, we’ll talk about subnet masks a little bit in default gateways. Then we’ll look at configuring a network interface.

We’ll look at how to do it on Solaris Eleven using the config command as well as other commands that are kind of new to you that Solaris Eleven includes such as ipadm and Dladm. We’ll also use those same commands to learn how to administer a network interface, how to change some of its properties and so forth, how to change which network configuration profile is used on the network configuration. That’s something new that Solaris Eleven offers is network configuration profiles. We’ll also look at how to verify network operation and we’ll use the basic commands like ping and so forth, but we’ll use some other commands to verify certain services are working and that they can communicate on the network. We’ll also determine the data link availability and that has different meanings depending upon your background and experience and what you think data link means, we’ll explain what it means in terms of Solaris Eleven and how to determine whether the data link is available or not and how to resolve issues when it’s not.

And speaking of resolving issues, we’ll also talk about troubleshooting network issues from very basic to somewhat complex network issues using some of the built in commands and management interfaces that we have available to us on Solaris Eleven. So that’s what we’re going to cover in a nutshell. And we’ll go into all these topics a little bit more in depth. But keep in mind, some of this may be review for you and some of it may be new concepts. So it’s a good idea to go through and follow through all the lessons that we talk about. The other thing is that we’re not going to cover most things outside the client level. We’re really talking about connecting a client to the network, not necessarily providing network services again like Web services, DHCP services, DNS services, and so forth. So it’s very system or client centric. So as long as you’ve keep those things in mind and understand that there’s probably a lot more you could learn and probably will learn in the course of your practicing and studying for the OCA, than we’ll be fine during this particular discussion. So let’s go ahead and jump into it.

2. Basic Networking Concepts pt. 1

Now let’s talk about some basic networking concepts. Now Solaris Eleven is no different than Windows, Linux or other brands of Unix in that it uses standard TCP IP protocols, hardware naming conventions, cabling, and so forth to connect to networks. Now, there are some specific things that apply to Solaris Eleven, such as network configuration profiles and so forth, that we won’t discuss right now. We’ll discuss those in next few sessions when we talk about those things. This session we’re going to talk about some basic network concepts. Not necessarily solar specific ones, but things that apply to network in general. And we know that you’ve probably seen a lot of this before. If you’re an experienced administrator with a system of any type, you’ve probably done network configuration before. But this will serve just as a reminder and kind of get you back into the thinking mode of networking. Now, networks without going to a great deal of information on the OSI model and the TCP IP stack typically require three basic elements pieces of information to connect to a network. Now, for the purposes of our discussion, we’re going to talk about IP version four versus IP version six later on. We may touch on some IP version six things occasionally, but we’re going to really discuss IPV four right now. Now, the IP address is one of the things that we need to connect to a network.

It’s a unique number on a network that basically identifies our specific network and our host. So it tells the network who we are. Specifically. There’s a thing called a subnet mask that goes with this IP address. The two are always connected. You almost always see them together. This subnet mask tells the computer itself which network it’s on. In fact, it differentiates between the network ID and the host ID within the IP address. Now, there’s another thing we almost always need, and it’s called the default gateway. Now, the default gateway is the IP address of the router that the network is connected to. And what happens if you send traffic out from your box? Typically, if it’s not intended for the network you’re connected to, it needs to go beyond that network. Well, the only way it can do that is to go through a router. And that router is the default gateway address. If you were only going to send traffic to only your own internal network of four or five computers, then you might not need a default gateway, but you wouldn’t get very much done.

So a default gateway is almost absolutely necessary to connect to the network and definitely necessary to connect to the Internet. So you’ve got those three pieces of information, but you also may have other things that you really need to get on the network or the Internet with. The first is the DNS address. Now, keep in mind, we’re talking from the client perspective. There’s a DNS service out there on something called a DNS server that resolves human readable Internet names to IP addresses. So www. oracle. com is typically resolved to whatever the IP address is, and that server does that.

However, on the client side, our machine needs to have a DNS server’s address configured into it so it knows how to contact the DNS server to perform this name resolution process. So that’s another piece of necessary information is a DNS address, and typically that will help us resolve human readable names to IP addresses. The other thing we need is a method to configure IP information on our system or host. Now, there’s two ways we can do this. We can use a static method, which means a human being has to go to each system and manually type in an IP address, subnet, mass default gateway, DNS information, and so forth. And that actually can be timeconsuming and prone to errors. DHCP, on the other hand, is a service that’s run by a DHCP server on the network and it gives that information out to clients as they boot up so that no human has to go around and do this. And this makes it faster, more efficient, and less error prone. Now, all of these items are typically necessary to effectively communicate on any network, and sometimes more importantly, the Internet.

You kind of need all of these elements to make it work good. And we haven’t really even discussed things like how to configure email or your web browser or proxy servers and things like that. This is just the minimum elements necessary from the TCP IP’s perspective to communicate on the network. Now, let’s talk about something else in our concepts discussion. There’s a thing called a Nic, a network Interface card that’s actually the hardware card that fits into your system that runs to the cable that runs to the network. Now, each of these nix have a hardware or physical address burned to a chip on the card. We call this the Media Access Control, or Mac address. This Mac address is a twelve digit hexadecimal number, and I’ve given you an example of one on the screen. And basically it’s used in certain instances to communicate at certain levels on the network, typically at the physical data link and Media Access Control layers of the OSI model.

Now, you don’t need to know too much about the Mac address at this point. We’ll talk about those a little bit later. But understand that the first six digits are manufacturer specific and the second six identify the unique card itself. Now, above certain layers we use really the logical address, not the physical address, and that’s usually the IP address. And again, we’ll talk about that a little bit later as we go. So what I want to do now is actually show you a couple of ways you can look at the IP address information on your computer just so you can find it and identify it. So let’s go take a look at that okay, there’s a couple of different ways we can look at IP addressing information on our Solaris eleven box. One of them is through the ipadm command and we get to see our network interfaces there and our IP address information. We can also run the good old if config command and we run it with the interface and we can see that information on the interface itself. ipadm is more of a solarispecific command, whereas if configured is a little bit older. So now we have two ways to look at IP addressing information.

3. Basic Networking Concepts pt. 2

Now that we’ve covered some basics of networking, just as a refresher to it, let’s talk a little bit more about specific things that apply to Solaris Eleven. Now, Solaris Eleven uses the same TCP IP protocol, stack services, ports, protocols, hardware, standards, wiring, and so forth. So by and large, it’s not very difficult to understand, use and troubleshoot when you need to. Therefore are some things that are different a little bit, though. It uses some different processes, commands, and applications to manage networks, and you do need to know these. For the exam, there are several command lines that you need to know, as well as how to use some of the GUI tools, and we’ll talk about those here in a second. One of the things that’s unique to Solaris Eleven is a concept called Network Configuration Profile, or NCP. Now, these NCPS help you to configure and manage the system’s network connection. And you can have several network configuration profiles on the box, but only one can be active at a time. Now, there are two types of NCPS, one called reactive and one called fixed. Now, as you might expect, the reactive one will adjust the network configuration if network conditions change. For example, if you’re connecting on a laptop to a network at work that has DHCP enabled, and you can keep that configuration. However, if the DHCP server goes down, the network can automatically reconfigure with a predefined static IP address. So it’s reactive. If the network conditions change, it will change as well. The reactive NCPS can also correspond to a predefined location, and location might be work, your office, your home, and so forth. It can also correspond to a location in terms of whether it’s no network connectivity or automatic connectivity and so forth.

And you can have many different reactive NCPS configured, but typically only one active at a time. Now, fixed NCPS are the other type, and they define a specific network configuration on the system, but it does not automatically adjust that configuration if the conditions change or vary. Now, unlike reactive NCPS, there can only be one fixed NCP configured at a time on the box. So you may have several reactive NCPS and one fixed. Now, when you first install the system, there are two system generated NCPS by default. There’s one that’s automatic and one that’s fixed. And the default fixed is what the fixed one is called, and the automatic one is what the reactive one is called. And you can change these and add more to them, at least the reactive ones. The fixed one, you can only edit. Now, there are a couple of different ways to edit these NCPS. One is through the GUI, which we’ll look at, and one is through the Net adm command, and it’s used to administer these NCPS. Let’s go ahead and take a look at the GUI, and then we’ll look at the command line utility. All right, we’re back in Solar Salon first thing I want to look at is to show you the network utility here.

And there are several different things that shows you your connection status and will show you all the different enabled connections or IP address and so forth. But what we’re more interested in is looking at the network profiles. Right now it shows that we have a network profile of automatic and the location of automatic. Now we can set and change locations here. We can edit these and add locations. We can also go and look at the profiles themselves. We have the automatic and default fix. These are the system generated ones that are always installed when Solaris is installed. If you click the automatic one you can edit it, you can also duplicate it and change it so that you don’t mess up the original one. So if you click edit you’ll see there’s different things that you possibly could edit in here. It’s better to go ahead and duplicate this and then edit it for the default fixed, there’s not much you can do to it.

You can view it. But if you look down here you can see that profiles of type fixed can only be edited using Dladm and ipadm. So you’ll need to use those commands to edit this default fixed one. Now again, you can edit the automatic one in this particular facility, let’s say cancel and go to command prompt. And one of the things we want to look at is the net adm command and we’re just going to say list with the X on it and it’s going to list all of our profiles here and what their state is. We have the default fix which is disabled currently because remember, only one can be online at a time. And then we have the automatic one that’s online inactive. So you’ve got some other ones here that are incidental to this and some location ones that apply to the automatic one like the no net, the automatic and so forth.

And the two commands, the Dladm command and the ipadm command they can use to edit these, we’ll look at a little bit later, because they do all kinds of things on your box with your network, and we’ll look at those when we look at configuring and managing your network interfaces, so we’ll get a chance to see those in action. But your net adm command can also enable or disable or make active a particular profile. If you just said netadm enable and then and then NCP and the name of the profile, it would go ahead and activate it. We’re not going to do that right now. So that’s basically profiles that’s unique to Solaris Eleven and we’ll take a look at how to edit them and some other things we can do with them. When we look at configuring and managing the network interfaces.

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