The ftpd 1M man page describes the services provided by the daemon in. It is implemented as the program telnet on local machines and the daemon in. Telnet provides a user interface through which two hosts can communicate on a character-by-character or line-by-line basis.
The application includes a set of commands that are fully documented in the telnet 1 man page. TFTP - The trivial file transfer protocol tftp provides functions similar to ftp , but it does not establish ftp 's interactive connection. As a result, users cannot list the contents of a directory or change directories. This means that a user must know the full name of the file to be copied. The tftp 1 man page describes the tftp command set. Thank you! We truly value your contribution to the website.
Telnet, a terminal emulation protocol, provides remote access to servers and networking devices. The internetwork layer equates to the network layer of the OSI model. The transport layers are the same in both models. It is responsible for formatting, compressing, and encrypting data, and is used to create and maintain dialog between source and destination applications.
DNS is used to translate domain names to IP addresses. SNMP is used for network management traffic. Explain: When a user types a domain name of a website into the address bar of a web browser, a workstation needs to send a DNS request to the DNS server for the name resolution process. The eMule application is P2P. Sharing a printer on a workstation is a peer-to-peer network.
Using ARP is just a broadcast message sent by a host. Interconnest the two PCs with two crossover cables and a hub. Which LAN segments will affected by the excessive broadcasts?
Only the Only the link between Both the Only the links between Two routers are connected via their serial ports in a lab environment. The routers are configured with valid IP addresses, but they cannot ping each other. What could be the cause of this problem?
The no shutdown command has not been applied to the interfaces. The clock rate command has not been entered on the DCE interface. The interface timers are not cleared. The FastEthernet interface is emulating a serial interface by assigning it a timing signal. Which layered network model is shown in the diagram? Host A is unable to reach host B on the remote network. A technician attempted to ping the local gateway and the ping was successful. To verify the host configuration, the technician issued the ipconfig command.
The local NIC is incorrectly configured. The subnet mask on host A is incorrectly configured. The IP address on host A is incorrectly configured. The default gateway on host A is incorrectly configured. Which option shows how a router will route packets to a remote network?
Correct answer is image 4! An organization has been assigned network ID Which IP address range can be used for this organization?
A network administrator is configuring several switches for a network. The switches have similar configurations and only minor differences. The administrator wants to save all commands that are issued on the first switch to a text file for editing. Which transfer option should be selected in HyperTerminal?
When must a router serial interface be configured with the clock rate command? Due to a security violation, the router passwords must be changed. What information can be learned from the following configuration entries? Router config line vty 0 3 Router config-line password c13c0 Router config-line login. The entries specify three Telnet lines for remote access. The entries specify four Telnet lines for remote access.
Telnet access will be denied because the Telnet configuration is incomplete. A network technician is trying to determine the correct IP address configuration for Host A. What is a valid configuration for Host A? IP address: Which prompt represents the appropriate mode used for the copy running-config startup-config command? The tracert command is initiated from PC1 to PC4.
Which device will send a response to the initial tracert packet from PC1? Which information is used by the router to determine the path between the source and destination hosts? A PC is communicating with another PC on a remote network.
The two networks are connected by three routers. Which action will help to identify the path between the hosts? Use the ipconfig command at the host. Use the tracert command at the host. Use the ping command at the destination. The diagram represents the process of sending e-mail between clients. Which list correctly identifies the component or protocol used at each numbered stage of the diagram?
MUA 2. MDA 3. MTA 4. SMTP 5. MTA 6. POP 7. MDA 8. MUA 1. POP 3. MDA 4. MDA 7. SMTP 8. SMTP 4. MDA 5. SMTP 7. POP 8. SMTP 3. The router of the company failed and was replaced. After the replacement, hosts C and D in the Education office are able to ping each other, but they are unable to access the hosts in the Accounts office.
The IP address at the serial interface of the router is incorrectly configured. The hosts in the Accounts office are not on the same subnet as the hosts in the Education office. Host A and B are unable to communicate with each other. Host A is assigned a network address. Host B is assigned a multicast address. Host A and host B belong to different networks. The gateway addresses are network addresses. The packet inside the captured frame has the source IP address What is the destination MAC address of the frame at the time of capture?
D EE03 While configuring a network, a technician wired each end of a Category 5e cable as shown. Which two statements are true about this setup? Standards track RFCs pass through three maturity levels before becoming standards:. This is a protocol specification that is important enough and has received enough Internet community support to be considered for a standard.
The specification is stable and well understood, but it is not yet a standard and may be withdrawn from consideration to be a standard. This is a protocol specification for which at least two independent, interoperable implementations exist. A draft standard is a final specification undergoing widespread testing. It will change only if the testing forces a change. A specification is declared a standard only after extensive testing and only if the protocol defined in the specification is considered to be of significant benefit to the Internet community.
There are two categories of standards. A Technical Specification TS defines a protocol. An Applicability Statement AS defines when the protocol is to be used. There are three requirement levels that define the applicability of a standard:.
This standard is optional. It is up to the software vendor to implement it or not. Two other requirements levels limited use and not recommended apply to RFCs that are not part of the standards track.
A protocol is " not recommended " when it has limited functionality or is outdated. There are three types of non-standards track RFCs:. An experimental RFC is limited to use in research and development. A historic RFC is outdated and no longer recommended for use. An informational RFC provides information of general interest to the Internet community; it does not define an Internet standard protocol. But there are several interesting FYI documents available. BCPs formally document techniques and procedures.
BCPs that provide operational guidelines are often of great interest to network administrators. There are now more than 3, RFCs. As a network system administrator, you will no doubt read several. It is as important to know which ones to read as it is to understand them when you do read them.
To understand what you read, you need to understand the language of data communications. RFCs contain protocol implementation specifications defined in terminology that is unique to data communications.
To discuss computer networking, it is necessary to use terms that have special meaning. Even other computer professionals may not be familiar with all the terms in the networking alphabet soup.
As is always the case, English and computer-speak are not equivalent or even necessarily compatible languages. Although descriptions and examples should make the meaning of the networking jargon more apparent, sometimes terms are ambiguous. A common frame of reference is necessary for understanding data communications terminology.
An architectural model developed by the International Standards Organization ISO is frequently used to describe the structure and function of data communications protocols. This architectural model, which is called the Open Systems Interconnect OSI Reference Model , provides a common reference for discussing communications.
The OSI Reference Model contains seven layers that define the functions of data communications protocols. Each layer of the OSI model represents a function performed when data is transferred between cooperating applications across an intervening network. Figure identifies each layer by name and provides a short functional description for it. Looking at this figure, the protocols are like a pile of building blocks stacked one upon another.
Because of this appearance, the structure is often called a stack or protocol stack. A layer does not define a single protocol—it defines a data communications function that may be performed by any number of protocols. Therefore, each layer may contain multiple protocols, each providing a service suitable to the function of that layer.
For example, a file transfer protocol and an electronic mail protocol both provide user services, and both are part of the Application Layer. Every protocol communicates with its peers. A peer is an implementation of the same protocol in the equivalent layer on a remote system; i.
Peer-level communications must be standardized for successful communications to take place. In the abstract, each protocol is concerned only with communicating to its peers; it does not care about the layers above or below it.
However, there must also be agreement on how to pass data between the layers on a single computer, because every layer is involved in sending data from a local application to an equivalent remote application. The upper layers rely on the lower layers to transfer the data over the underlying network. Data is passed down the stack from one layer to the next until it is transmitted over the network by the Physical Layer protocols.
At the remote end, the data is passed up the stack to the receiving application. The individual layers do not need to know how the layers above and below them function; they need to know only how to pass data to them. Isolating network communications functions in different layers minimizes the impact of technological change on the entire protocol suite.
New applications can be added without changing the physical network, and new network hardware can be installed without rewriting the application software. The Application Layer is the level of the protocol hierarchy where user-accessed network processes reside. This includes all of the processes that users directly interact with as well as other processes at this level that users are not necessarily aware of.
For cooperating applications to exchange data, they must agree about how data is represented. The Transport Layer in the OSI reference model guarantees that the receiver gets the data exactly as it was sent. The Network Layer manages connections across the network and isolates the upper layer protocols from the details of the underlying network.
The reliable delivery of data across the underlying physical network is handled by the Data Link Layer. The Physical Layer defines the characteristics of the hardware needed to carry the data transmission signal. Features such as voltage levels and the number and location of interface pins are defined in this layer. As in the OSI model, data is passed down the stack when it is being sent to the network, and up the stack when it is being received from the network.
Each layer in the stack adds control information to ensure proper delivery. This control information is called a header because it is placed in front of the data to be transmitted.
Each layer treats all the information it receives from the layer above as data, and places its own header in front of that information. The addition of delivery information at every layer is called encapsulation. See Figure for an illustration of this. When data is received, the opposite happens. Each layer strips off its header before passing the data on to the layer above. As information flows back up the stack, information received from a lower layer is interpreted as both a header and data.
Each layer has its own independent data structures. Conceptually, a layer is unaware of the data structures used by the layers above and below it.
In reality, the data structures of a layer are designed to be compatible with the structures used by the surrounding layers for the sake of more efficient data transmission. Still, each layer has its own data structure and its own terminology to describe that structure. The Internet layer views all data as blocks called datagrams.
Most networks refer to transmitted data as packets or frames. Figure shows a network that transmits pieces of data it calls frames. The protocols in this layer provide the means for the system to deliver data to the other devices on a directly attached network.
This layer defines how to use the network to transmit an IP datagram.
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