With the growth of the Internet and lower cost of PC’s, doing a comparable summary on what to buy i.e. PC -v- Mac is almost redundant and irrelevant these days. Add to that the growth of home networking so mom, dad, and the kids can all share the same printer and Internet connection, I figured it’d be worth adding a little breakdown on networking in general.
This is not an all inclusive structure of computer networks, its a simple basic summary. Todays design of networks are still as they were 10, 15, even 20 years ago, but the need for security has increased and the means to get your different systems connected has changed, slightly. Your systems, Linux, Windows XP, Windows Vista, Windows 7, and MAC’s all have different ways to join a network. Heck, even the different versions of an OS (Operating System), such as Windows 7 Home Edition -v- Windows 7 Pro are slightly different do to the structure of each one and I strongly suggest that you research the networking ability and limitation of each system you want to network.
So I hope this helps a little, those of you considering building your own home network.
The Basics:
As the importance and understanding of information control, retrieval, and sharing becomes more apparent in our society, persons involved in the field of computers or information technology must have, as a minimum, a basic understanding of networking, its terms, and its practices. This applies to everything from small businesses and large corporations, to the Internet and world wide systems. This need for understanding how to network computers together is also becoming more and more apparent for home users as the Technology Revolution expands and grows.
In this post I will cover many basic concepts and key terms to familiarize you with the basics of networking. While many of the concepts that we will cover are global, in other words, they apply to any operating system or network type, the sheer number of proprietary systems, network protocols, and operating systems prohibits an all inclusive discussion of networking here. Because of this we will focus on the “basic” concept of the Microsoft model and its uses. This is not because Microsoft offers the best choice, just the most prevalent common set of systems that you may encounter. Other systems that you may wish to cover on your own are the Novell, Unix (Linux), and Macintosh (Apple) systems.
1. What is Networking?
Networking is a term used to describe the connection of two or more computers to allow for communication and the exchange of information. Networks can range from simple workgroups of only two computers, up to extremely large networks ranging over countries and continents. The World Wide Web is an example of a large network that spans the globe. In order to understand different types of networks we must first be able to understand several key concepts and terms.
Workgroups
A workgroup is a simple network where computers are connected together via some connector, where administration of the network is decentralized. All resources on the network are controlled locally on each machine. This is often referred to as a Peer-to-Peer Network, with each computer on the network representing a Peer.
Domains
Domains are comprised of a number of computers in a network and controlled by a domain controller, called a server. This is the client server model. The server is responsible for centralizing administration of the network into one location and managing the permissions of resources on the network. This is extremely important in setting continuous and standardized security on a network.
Most networks are actually combinations of peer-to-peer and Client Server models, where the server controls security and access to some resources, while peers set individual permissions on their machine to allow others on the network to access information or hardware, if this is allowed by the Server permission settings. The person, or persons, responsible for maintaining the server, security, and network systems is called the Administrator.
Servers can serve many roles, and often serve multiple roles. They can be one or any of the following:
1. File Server
2. Print Server
3. Enterprise Server
4. Database Server
5. Web Server
LAN
A LAN ( Local Area Network ) is a network in a single geographic location. Several floors of a building attached to the same Network is an example of a LAN. Several computers in the same room attached to the same network is also a LAN.
WAN
A WAN ( Wide Area Network ) is a network where network participants are removed from each other geographically. This can be across town, across a nation, or across the world.
II. What Kind of Network is Right for You?
There are several factors to review before determining what kind of network is best for you. These include, but are not limited to:
1. Cost
2. Scalability
3. Security
4. Application Deployment
5. Back Operations
6. Organization
Let’s look at some of the benefits and problems with each type of network.
Workgroup ( Peer to Peer )
Pros
- Lower cost in equipment. No server hardware or software needed.
- Easy Setup
- No network administration required
- Users can control their own resources and their sharing
- No reliance on other computers to operate
Cons
- Additional load on computers because of sharing of resources
- Cannot handle as many network connections as servers
- Lack of Central Administration, harder to organize and locate information
- Users must administer their own machines and shares
- Weak security
- Multiple Passwords for shared resources across the network
Server Based Networks ( Client –Server )
Pros
- Strong Centralized Security
- Central File Storage. This allows clients to access, update, and work with data easily from a single location. Simplifies back up requirements
- Servers can pool available hardware and software, lowering costs
- Sharing of expensive equipment from a single location ( i.e., laser printers, document centers )
- Faster at sharing resources
- Client Users do not have to worry about resource sharing or administration tasks
- Single password sets permissions for shares on network
Cons
- Expensive Dedicated hardware and software
- Network Administrator Required – more expensive
You should also consider such possibilities as networks growing and expanding over time, deploying software to multiple computers, Client-Access Licenses ( Server Based ), Intranets, email, and, web presence.
In addition to the actual type of network you will need to consider how these computers will be connected. Will you implement routers, hubs, switches, or other equipment? These are all crucial in planning for the correct type of network.
III. Network Topology
Once a type of network has been decided on, you must consider the physical layout of your network. This will determine equipment required, and aid you in tracking down problems with a network. There are several types of physical layouts ( topologies ) that we will cover. They are:
- BUS
- Star
- Ring
There are many more types of networks, but these are the most common and most likely topologies that you will use.
BUS Topology
Bus networks are simple networks, wherein a cable is attached to each computer with no active electronics to boost or amplify the signal. This classifies bus networks as passive. When one computer sends a signal over the network, each computer receives the signal, until the destination computer receives it. If the signal is not meant for a computer, it simply ignores it. Only one computer can send a signal at a time, therefore, network speeds can be very slow. Bus networks also require terminators at each end of the cable connecting the computers. If terminator are not used, the signal passes up and down the cable until it dissipates. This is called ringing.
Star Topology
In a star topology each computer is connected via a cable to a centralized point called a hub. When a signal is sent from a computer, it passes through the hub to the destination computer, or to all computers if the hub is in broadcast. Star networks are easy to expand as hubs can be hooked together to achieve large numbers of computers on the network.
Ring Topology
In a ring topology each computer is connected to another computer in a ring. Each computer on the network receives the signal generated by another computer until the destination in reached. This makes the network active. Terminators are not needed as there is no physical end to the ring.
Pros
- Equal access to the network by all machines
- Graceful degradation of performance as machines are added
Cons
- The failure of one machine causes the entire network to fail
- It is difficult to troubleshoot
IV. Network Media
In order to connect a network together, we must use some sort of media. While there are several types that we will discuss, we will focus on wire connections as they are the most common and practical for most networking environments.
Copper
Copper wire represents the single largest method of connecting computers in a network. Why? It is simple, cheap, and fairly reliable. Engineers have become quite good at utilizing copper to transport information across long distances with good reliability. We can see examples of this in our phone systems, CAT 5 cable, and coaxial cable. The primary drawback to copper is that it offers resistance beyond specified lengths ( check with your manufacturer for specifics on each type of media. This can range from 100 feet to well over 300 and beyond ) and it is susceptible to interference from outside sources. To help with these problems, repeaters can be used to boost signals, and shielding is used to help prevent noise and interference across a copper line. Often, this shielding is part of the construction of the cable, but additional shielding may be required in areas where interference is a problem.
Wireless
Wireless communication over a network can take many forms. These include Radio and Infrared. These forms of connections offer the benefit of no physical media between connection points. This is very helpful in distant locations and where mobility is a requirement. The primary drawbacks here are speed, terrain obstacles, and interference. While improvements have been made and speeds are increasing, these types of connections are still slow by copper and fiber optic standards. They can also be limiting when line of site is required to establish and maintain a connection. Interference, especially from such common items as cordless phones can offer very difficult problems to overcome.
Fiber Optic / Glass
Fiber optic cables offer a great deal in advantages. They are extremely fast, do not suffer from interference, and are incredibly reliable. The biggest drawback is cost. Fiber optics are very expensive and often are not a viable solution for a local network. This form of connection is often reserved for large connection points (ISP’s) and transnational connections, especially when crossing oceans. However, Fiber is becoming more reasonable priced and more and more businesses are moving to Fiber Optic Networks.
As the most common and practical networking media is copper, we will focus on this for the purposes of this instruction. While Coaxial cable has been very common, today’s networks are primarily constructed with CAT-5 cable, CAT-6 is becoming more prevalent in the commercial environment as it has the same physical structure but greater speed capabilities.
CAT ( short for category ) 5 is comprised of 4 pairs of twisted wires that terminate into an RJ-45 connector. When making a connector it is imperative that the correct sequence is followed in order to assure that signals passed through the cable are sent and received in the same manner. There are two types of cables that you can buy or make: straight and cross-over. Within the straight form there are 2 accepted manners in which to cable. These are illustrated below.
It is always a good idea to have a tester on hand to make sure that your cables work correctly before you put them in place. Crossover cables are generally used for up-linking hubs or other devices that do not have standard uplink ports.
One of the biggest considerations when installing cable is the actual layout of the cable, where you will place your drops ( locations where the cable is exposed to allow computers to connect ), and how you will bind the cable together for neatness. As most of your cable will be hidden in walls, sub-floors, crawl spaces, and ceilings, the consideration surrounding items is key. Hot pipes might melt your cable. Fluorescent lights can cause interference, causing bad signals and network connectivity. Distances are also a consideration. Generally, Cat 5 cable can be run for about 300 feet before signal degradation, so signal boosters or repeaters may be needed. Check with your cable guidelines for accurate information about this.
While simply laying out cables for connecting to a PC or hub may seem simple, it is also very unsightly. You should become familiar with exposed conduit and boxes for your cable to give a more professional appearance. You should also consider how you will bind cables together into a snake. While there are many forms of these wraps, perhaps the most efficient is Velcro straps. They allow for tight binding without pinching the cable, and allow for the easy removal and addition of cables from your snake.
Finally, you should consider labeling your cables at intervals. This interval can be anywhere from every 15 feet to every 30 feet. This is helpful should you, or another person, have to come back and remove cable or re-route it.
V. Protocols and Related Systems
A protocol is a set of standards by which communication rules are established and carried out. Perhaps the easiest way to categorize this is to think of each protocol as a separate language, much like English, Spanish, German, or French. In order for two or more computers to communicate, they must be able to speak a common language. There are a host of protocols, each of which could be covered in depth in its own massive volume. Here we will concentrate on the most common and important, covering the essentials to understanding them.
TCP/IP
Transmission Control Protocol / Internet Protocol, is perhaps the most common and widely used protocol suite today. It is the protocol suite used for most networks in Microsoft products, and the Internet. Before we can delve into TCP/IP we must first understand some basics about the construction of the protocol and how it communicates.
The first thing we must understand is the basic construction of the packets used in TCP/IP. A packet is a unit of information that is transmitted as a whole across a network. All items of information used in networking are broken down into these smaller packets. Each of these packets are made up of layers that perform different functions for communication called protocol stacks. While most of these stacks are made up of 7 layers, the model used by TCP/IP only consists of 4. These are grouped together to accomplish the same function of the 7 layer model.
Below is a brief explanation of each layer and its function. For a more in depth explanation of each, consult third party publications and websites.
Process / Application – This layer deals with the ability of one application to communicate with another, regardless of the platform, operating system, or other features. Examples of applications that use this layer are FTP, Telnet, TFTP, SMTP, and SNMP. (These will be discussed in detail later on).
Host-to-Host – This layer is designed to shield the upper layer applications from the complexities of the network. The two main protocols of this layer are TCP and UDP (User Datagram Protocol). The primary job of this layer is to set up communication prior to the Process / Application layer actually sending information. It splits large amounts of data into small segments. It then contacts the destination machine to determine an acceptable size for these segments for transmission. It also tests for errors in transmission, resends data as needed.
Internet – This layer serves the function of routing and providing a single interface for the upper layers. This is key in the sending and receiving of information across networks and the Internet. We will cover addressing a little later.
Network Access – This layer can be thought of as the traffic cop for the entire stack. It’s job is to turn all of the information into binary, detect retransmissions and collisions, specifying the MAC address (the physical address of a piece of hardware), specifying the physical media to be used, timing rules, and access methods for the network.
This may seem a bit confusing, but do not worry. Your primary focus will be on the IP addressing section. I have only included the above for a reference to understand that there is a lot of work being done behind the scenes that most people never see or know about.
IP Addressing
IP addressing is the system by which each network and machine (host) on a network receives a unique address. This address is represented in decimal format as XXX.XXX.XXX.XXX, with the lowest value being 0 and the highest being 255 for each section. Each of these addresses is made up of 32 bits of information. These 32 bits are divided into 4 sections, each being 1 byte, or 8 bits. To understand this we will need to be able to understand binary.
Binary is a system of numbers comprised of 0 and 1. If we were to take a decimal address, 127.41.5.2 and convert it to binary we would get 01111111.00101001.00000101.00000010.
This may be confusing at first, but there are simple ways to understand this. Perhaps the simplest is to look at binary as simple math (which it is) using exponents. Examine the chart below.
| Binary | Decimal | Math Conversion |
|---|---|---|
| 00000000 | 0 | |
| 00000001 | 1 | 20 + 1 = 1 |
| 00000010 | 2 | 21 + 0 =2 |
| 00000100 | 4 | 22 + 0 =4 |
| 00001000 | 8 | 23 + 0 =8 |
| 00010000 | 16 | 24 + 0 =16 |
| 00100000 | 32 | 25 + 0 =32 |
| 01000000 | 64 | 26 + 0 =64 |
| 10000000 | 128 | 27 + 0 =128 |
| 11111111 | 255 | 27 + 26 + 25 + 24 + 23 + 22 + 21 + 1 |
You should notice that the exponent is directly related to the place of the 1 or 0. The furthest right place being 0 and the furthest left being 7. If you do not understand exponents, the simplest was to explain it is the number (in this case 2) being multiplied by itself the number of times indicated by the exponent. For example, 24 is the same thing as saying 2 x 2 x 2 x 2, which equals 16. Here are some further examples of translating Decimal addresses to binary. We will start with 1 byte (8 bits) and progress to include all 4 bytes (32 bits) of an IP address.
| Decimal | Binary |
|---|---|
| 25 | 00011001 |
| 239 | 11101111 |
| 125.67 | 01111101.01000011 |
| 207.149 | 11001111.10010101 |
| 68.25.124 | 01000100.00011001.01111100 |
| 186.87.65 | 10111010.01010111.01000001 |
| 207.15.68.9 | 11001111.00001111.01000100.00001001 |
| 226.214.4.192 | 11100010.11010110.00000100.11000000 |
Why do you need to know this? Simple, sub-netting. If you are setting up a network, you will most likely run across sub-netting and you must be able to accomplish it. We will cover that shortly. Before that you need to understand the three classes of IP addresses: Class A, Class B, and Class C.
Class A
Class A addresses are used for systems with a small number of networks and a large number of hosts. The format for the Class A network is NETWORK.HOST.HOST.HOST. In other words, the first byte is reserved to identify the network and the three remaining bytes are used to designate hosts. Class A Networks are designated as 0-127 for the first byte. But, here we run into a problem, namely reserved addresses.
Reserved addresses are IP addresses that were set aside to perform specific functions. Below is the list of reserved IP’s.
| Description | Purpose |
|---|---|
| Network address of all zeros | Means “this network” |
| Network address of all ones | Means “all networks” |
| Network 127 | Loop back tests. Packet is sent from a computer back to itself without actually generating network traffic |
| Host / node address of all zeros | Means “this node / host” |
| Host / node of all ones | Means all nodes on the network |
| Entire IP set to all zeros 0.0.0.0 |
Designates default route in RIP protocol |
| Entire IP set to all ones 255.255.255.255 |
Broadcast to all nodes / hosts on network |
Now that we know that 0.X.X.X is taken up as a reserved address for specifying “this network”, our Class A is actually limited to only 127 possibilities for the number of networks.
Class B
Class B Networks are used to provide an equal number of hosts and networks.Class B addresses are designated by the first byte of the address with the values ranging from 128 to 191. The first 2 bytes of the IP address are reserved for the network, the last 2 for the node / host. NETWORK.NETWORK.HOST.HOST
Class C
Class C Networks are used to provide a large number of networks with few nodes / hosts. This class is designated by the first three bytes to specify the network and the last byte to specify the host / node. NETWORK.NETWORK.NETWORK.NODE The range of values for Class C addresses ranges from 192 to 223 in the first byte.
Subnet Mask
Subnet masks are used for several purposes. The most common of these is breaking up larger network segments into smaller ones. This would be important for several reasons, mainly controlling the number of IP addresses that we use (avoiding waste) and adding additional security to our network. Let’s take a look at an example to explain and clarify this concept.
So your a network administrator for a local company, using a router to handle all of the traffic to the Internet (WAN) through a single IP address. Your router supports NAT (Network Address Translation) to allow you to use a large number of clients on your LAN side of the network that are able to reach the Internet (WAN). You have designated the internal network as 192.168.168.0. This means that you have all of the IP’s in the Class C IP range from 192.168.168.1 to 192.168.168.254 available for your client machines.
Now that you know the range of your IP’s, you want to further subdivide the network into two segments, keeping machines on one subnet from accessing the other. To do this you need to determine the subnet. In this case, as your only splitting the network into 2 sections, you have a relatively simple problem to figure out. How many bits are in the IP range? Earlier we discovered that each IP is made up of 32 bits, or four 8 bit sections. If your IP range is 192.168.168.0, you have 24 bits, with 8 left over. To subnet this network, more than 24 bits must be set to one on the left side of the subnet mask. For instance, the 25-bit mask “255.255.255.128” creates a two-subnet network as follows.
| network address (24 bits) | subnet number (1 bit) | extended network | host address range |
|---|---|---|---|
| 11000000 10101000 10101000 | 0 | 192.168.168.0 | 192.168.1.1 – 192.168.1.127 |
| 11000000 10101000 10101000 | 1 | 192.168.168.128 | 192.168.1.129 – 192.168.1.255 |
For every additional bit set to one in the mask, another bit becomes available in the subnet number to index additional subnets. A two-bit subnet number can support up to four subnets, a three-bit number supports up to eight, and so on. The 2 subnet configuration above gives me space for 126 clients per subnet section, effectively giving me two networks.
DHCP
Dynamic Hosting Control Protocol (DHCP) is a wonderful little tool that can save you time and effort with your network. In essence, DHCP allows clients to automatically receive an IP address, subnet, and gateway setting over a network from a DHCP server. Many routers and server operating systems support DHCP, including Windows Servers. In order to use Windows Server DHCP, a fixed, or static IP, must be assigned to the Server. Many routers now allow DHCP to be used for both the router’s IP address, and in turn, allow it to serve DHCP from this dynamic IP.
Each time an address is given from a DHCP server to a client, the client is obtaining a lease on that IP. The length of time is entirely dependent upon the way in which the DHCP server was configured. Administrators can have the leases last indefinitely, or require them to be renewed on a time system .For example, I could configure DHCP to offer leases that lasted only 5 minutes. Once a client machine has received an IP address from DHCP, it would be required to renew its lease every 5 minutes. The important considerations with the lease times are network traffic and availability of IP addresses. Shorter lease times will result in more network traffic as clients renew their leases. Longer leases will mean that the IP will be delegated for that time. This can be very important on a network that only has space for 30 IP’s, but has 50 users! You should be familiar with DHCP already. It is very common in Internet Service Providers. Once they have logged you onto their network, their server provides you with an IP for Internet access.
NetBios
Network Basic Input Output System is an application programming interface (API) that augments the DOS BIOS by adding special functions for local-area networks (LANs). Almost all LANs for PCs are based on the NetBIOS. Some LAN manufacturers have even extended it, adding additional network capabilities. NetBIOS relies on a message format called Server Message Block (SMB).
Server Message Block (SMB) is a message format used by DOS and Windows to share files, directories and devices. NetBIOS is based on the SMB format, and many network products use SMB. These SMB-based networks include LAN Manager, Windows for Workgroups, Windows Server, and LAN Server. There are also a number of products that use SMB to enable file sharing among different operating system platforms. A product called Samba, for example, enables UNIX and Windows machines to share directories and files.
WINS
Windows Internet Naming Service (WINS) is the solution offered by Microsoft for servers. In essence, WINS is a service that runs on a server that uses a database to map computer names to IP addresses on a network. This accomplishes several things.
First, it cuts down on a lot of the traffic across a network as computers search for resources on a network. Instead, they can access a single point on the network for their mapping needs.
Second, it offers a centralized location for modification and updates of network mappings, making administration much easier.
Third, it allows clients to browse resources and domains on the far side of a router without having a separate domain controller to list the resources.
LMHOST
The LMHOSTS file is commonly used on Microsoft networks to locate remote computers for network file, print, and remote procedure services and for domain services such as logons, browsing, replication, and so on.
Rules for LMHOSTS
Use the following rules for entries in LMHOSTS:
- Each entry should be placed on a separate line.
- The IP address should begin in the first column, followed by the corresponding computer name.
- The address and the computer name should be separated by at least one space or tab.
- NetBIOS names can contain uppercase and lowercase characters and special characters. If a name is placed between double quotation marks, it is used exactly as entered. For example, “AccountingPDC” is a mixed-case name, and “HumanRscSr /0x03” generates a name with a special character.
FTP
File Transfer Protocol (FTP) is a protocol within the TCP/IP suite for transferring files over a network (LAN or WAN) from one computer to another. The most common form of FTP is used with Internet Servers to specify sites and files that can be downloaded by users. FTP can be configured to allow either anonymous access to the public, or registered users. FTP requires a FTP Server and an FTP client. Some browsers support FTP browsing.
While there are many 3rd party solutions for FTP Servers, within the Microsoft environment, the most common implementation is with Internet Information Server (IIS). This is available as a standard component since Windows 2000 Server.
SMTP
Short for Simple Mail Transfer Protocol, SMTP is a protocol for sending e-mail messages between servers. Most e-mail systems that send mail over the Internet use SMTP to send messages from one server to another; the messages can then be retrieved with an e-mail client using either POP or IMAP. In addition, SMTP is generally used to send messages from a mail client to a mail server. This is why you need to specify both the POP or IMAP server and the SMTP server when you configure your e-mail application.
POP
Short for Post Office Protocol, POP is a protocol used to retrieve e-mail from a mail server. Most e-mail applications (sometimes called an e-mail client) use the POP protocol, although some can use the newer IMAP (Internet Message Access Protocol).
There are two versions of POP. The first, called POP2, became a standard in the mid-80’s and requires SMTP to send messages. The newer version, POP3, can be used with or without SMTP.
It may also be defined as Short for Point of Presence, a telephone number that gives you dial-up access. Internet Service Providers (ISPs) generally provide many POPs so that users can make a local call to gain Internet access.
PPP
Short for Point-to-Point Protocol, a method of connecting a computer to the Internet. PPP is more stable than the older SLIP protocol and provides error checking features.
DNS
Domain Name System (or Service) DNS is an Internet service that translates domain names into IP addresses. Because domain names are alphabetic, they’re easier to remember. The Internet however, is really based on IP addresses. Every time you use a domain name, therefore, a DNS service must translate the name into the corresponding IP address. For example, the domain name www.example.com might translate to 198.105.232.4. The DNS system is its own network. If one DNS server doesn’t know how to translate a particular domain name, it asks another one, and so on, until the correct IP address is returned. Microsoft has realized the power and ease of using DNS to aid in networks and subsequently incorporated it as its primary method of network name addressing since 2000, as opposed to NetBIOS.
VI. Networking Utilities
Ok, now that we understand, hopefully, some of the basic concepts behind networking, we need to be able to use certain tools to gain information about our networks. Here we will cover some basic integrated Microsoft tools that are used from the command line to inform us about our network. With any of these utilities you can simply type the name of the utility and then | help for detailed description and options. We are going to cover only the basics here.
PING
Pinging is much like pings in SONAR. By sending out a brief signal at a target we gain valuable information about the target. Namely if it even exists or is active, how long it takes our packets of information to get there and back, and if we are loosing any packets along the way. The simplest way to use ping is through the command line. Once you have one open simply type in the word ping followed by the destination address of the computer you are trying to reach. This can be in either IP or long name form. If I use the long name form (i.e.www.somewhere.com) the ping utility will translate the address to IP, displaying it for me. Below you can see an example of ping in action.
click on image for more detail
Notice that there is a great deal of information here.First, the fact that we received a reply, so the machine is there.Second, how long the trip took in milliseconds. Third, we have detailed summaries of how many packets were sent, how many were lost, average round trip time, with maximums and minimum. Ping is very useful for pinpointing network problems.
TRACERT
Trace Route is very useful for determining the route that your packets are taking along the network (LAN or WAN) to determine where network breaks or slowdowns are. Below is an example.
Click on image for more detail
While tracert is very helpful, you may want to consider a third party implementation of tracert. The most popular versions are Visual Route and NeoTrace. These applications not only perform the traditional functions of tracert, they also include visual maps and plotting of the routes so that you can actually trace the geography of your search. An IP address is nice, but knowing that a problem is occurring in Georgia, far beyond your control, is much better.
NETSTAT
Network Status displays the current TCP/IP connections on your computer. It can also be used to determine the number of packets that you have sent and received. Netstat is used by simply typing netstat at the command prompt. Below is an example.
Click on the image for a full view
NetUse
This utility is for usage with the Universal Naming Convention. Essentially, it is a tool by which you can map drives to network shares. This is helpful for connecting to files, folders, and hardware across a network. The common form of this utility is as follows:
NET USE * //DOMAIN/COMPUTER/SHARENAME
In this example, the * represents the next available drive letter assignment on your PC. You can specify a drive letter with the letter followed by a colon.Connecting to a printer is very similar, but instead of a drive letter or * you would substitute the correct LPT port. For example:
NET USE LPT1://DOMAIN/COMPUTER/PRINTERNAME
VII. Network Shares and Permissions
Now that we have the basic concepts behind the actual network, we need to learn how to implement it in a real world environment. Networks are useless unless we actually plan to share information across a network. We will cover both workgroup and domain types for sharing.
Permissions
There are several types of permissions, each with a varying level of access. Each of these levels is covered below.
Read – Allows a specified user or group to read information from the share. Users with this permission alone may not change, write, or take any other action with the share.
Write – Allows a specified user or group to read and write information from and to the share.
Change – Combination of both read and write permissions, along with the ability to delete files.
Full Control – Allows total control of the share, including taking control of the share. If someone takes control of a share they can change the permissions of that share.
Workgroup
In order to share resources, whether they be files or hardware, you must define explicit shares and permissions for each item. Unlike Domain level networks, you must manually enter each persons name an the password that they will use to access the share. These user names and passwords have nothing to do with a persons user name or password on a network. They may be the same or different. This is often very confusing and is not recommended if sharing hardware and software is your goal.
Domain
Sharing resources is much the same as in a workgroup, but in this case, a centralized list of users and their passwords is located on a server, allowing shares to be set more easily. Modifications to the shares and its permissions is also much easier. It also allows for a centralized location for shares on a server, or servers, instead of on individual clients, making security, back-ups, and monitoring much easier.
In order for sharing to be enabled and used, you must add the service to your network on each machine. To do this simply double click the Network icon in your control panel. Under Services choose Add and then choose Client for Microsoft Networks. Once this has installed close the network applet and reboot your machine. Once your machine has rebooted you will need to set your shares. To do this, simply right-click on the file, folder, or hardware device. In the menu that comes up, choose sharing. From here you can specify who has what level of access to the share. Once done click Apply and then Close. The resource is now shared across the network. You should be careful with the sharing option. Giving someone full control or change access must only be done if you are sure that this person has both the knowledge and capability to properly handle the share. Always give a person the lowest level of permissions required to do their job.
In a Windows Server environment, there are several rules on shares to understand. First, permissions are cumulative. In other words if John Doe is a member of the group Users and has both read and write control of a share, but as a user is not specified as an authorized user, nor specifically denied access, he will be able to access the share with read and write permissions. Second, specific denials of permissions take precedence over general rules. If in the same scenario I specifically deny John Doe Permission to the share, regardless of any permissions that he may have as part of a group, he will be denied permission to that share.
As a rule of thumb it is best to organize shares based on groups rather than individuals. This makes controlling and updating the share permissions much easier. For detailed information on all share rules and networking procedures, obtain a copy of the administrator’s guide for your Server platform.
Summary
We have covered quite a bit about networking. It is important to remember that, as with anything, there is no substitute for hands on experience and doing. In order to cover even the most basic of items with networking, you must apply these ideas and concepts. You must also remember that this is only a brief introduction and just begins to scratch the surface of the great landscape that is networking. Staying on top of networking, network administration, and related technologies is a never ending task that requires regular usage and research. With that, good luck and happy networking!
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