CCNA - Port

CCNA

Cisco Certified Network Associate

PORT

The term port can refer to either physical or virtual connection points. There are two kinds of port,

Physical port:

Physical network ports allow connecting cables to computers, routers, modems and other peripheral devices. Several different types of physical ports available on computer network hardware. A physical port, as opposed to a virtual or logical port is an interface on a computer into which you can insert a connector for a device.

Examples of Physical Port: RJ45 port (Ethernet/LAN/NIC Port), Serial Port (RS-232), USB Port.

Virtual port:

                Virtual ports are part of TCP/IP networking. These ports allow software applications to share hardware resources without interfering with each other. Computers and routers automatically manage network traffic traveling via their virtual ports.

Port numbers range from 0 to 65536, but only ports numbers 0 to 1024 are reserved for privileged services and designated as well-known ports. This list of well-known port numbers specifies the port used by the server process as its contact port.

Port Number	Description
1	TCP Port Service Multiplexer (TCPMUX)
5	Remote Job Entry (RJE)
7	ECHO
18	Message Send Protocol (MSP)
20	FTP -- Data
21	FTP -- Control
22	SSH Remote Login Protocol
23	Telnet
25	Simple Mail Transfer Protocol (SMTP)
29	MSG ICP
37	Time
42	Host Name Server (Nameserv)
43	WhoIs
49	Login Host Protocol (Login)
53	Domain Name System (DNS)
69	Trivial File Transfer Protocol (TFTP)
70	Gopher Services
79	Finger
80	HTTP
103	X.400 Standard
108	SNA Gateway Access Server
109	POP2
110	POP3
115	Simple File Transfer Protocol (SFTP)
118	SQL Services
119	Newsgroup (NNTP)
137	NetBIOS Name Service
139	NetBIOS Datagram Service
143	Interim Mail Access Protocol (IMAP)
150	NetBIOS Session Service
156	SQL Server
161	SNMP
179	Border Gateway Protocol (BGP)
190	Gateway Access Control Protocol (GACP)
194	Internet Relay Chat (IRC)
197	Directory Location Service (DLS)
389	Lightweight Directory Access Protocol (LDAP)
396	Novell Netware over IP
443	HTTPS
444	Simple Network Paging Protocol (SNPP)
445	Microsoft-DS
458	Apple QuickTime
546	DHCP Client
547	DHCP Server
563	SNEWS
569	MSN
1080	Socks

CCNA - OSI Layer

CCNA

Cisco Certified Network Associate

OSI Layer

1.       Application Layer

This layer supports application and end-user processes. Communication partners are identified, quality of service is identified, user authentication and privacy are considered, and any constraints on data syntax are identified. Everything at this layer is application-specific. This layer provides application services for transfers-mail, and other network software services. Telnet and FTP are applications that exist entirely in the application level. Tiered application architectures are part of this layer.

Eg: WWW Browser, FTP, HTTP, Telnet, Nfs, Snmp

2.       Presentation layer

This layer provides independence from differences in data representation (e.g., encryption) by translating from application to network format, and vice versa. The presentation layer works to transform data into the form that the application layer can accept. This layer formats and encrypts data to be sent across a network, providing freedom from compatibility problems. It is sometimes called the syntax layer.

Eg:  encryption, ASCII, EBCDIC, TIFF, GIF, PICT, JPEG, MPEG, MIDI.

3.       Session Layer

This layer establishes, manages and terminates connections between applications. The session layer sets up, coordinates, and terminates conversations, exchanges, and dialogues between the applications at each end. It deals with session and connection coordination.

Eg: NFS, NetBios names, RPC, SQL.

4.       Transport Layer

This layer provides transparent transfer of data between end systems, or hosts, and is responsible for end-to-end error recovery and flow control. It ensures complete data transfer.

Eg:  SPX, TCP, UDP.

5.       Network Layer

This layer provides switching and routing technologies, creating logical paths, known as virtual circuits, for transmitting data from node to node. Routing and forwarding are functions of this layer, as well as addressing, internetworking, error handling, congestion control and packet sequencing.

Eg: AppleTalk DDP, IP, IPX.

6.       Data link layer

At this layer, data packets are encoded and decoded into bits. It furnishes transmission protocol knowledge and management and handles errors in the physical layer, flow control and frame synchronization. The data link layer is divided into two sub layers: The Media Access Control (MAC) layer and the Logical Link Control (LLC) layer. The MAC sub layer controls how a computer on the network gains access to the data and permission to transmit it. The LLC layer controls frame synchronization, flow control and error checking.

Eg:  PPP, FDDI, ATM, IEEE 802.5/ 802.2, IEEE 802.3/802.2, HDLC, Frame Relay. 

7.       Physical layer

This layer conveys the bit stream - electrical impulse, light or radio signal  through the network at the electrical and mechanical level. It provides the hardware means of sending and receiving data on a carrier, including defining cables, cards and physical aspects. Fast Ethernet, RS232, and ATM are protocols with physical layer components.

Eg: Ethernet, FDDI, B8ZS, V.35, V.24, RJ45

CCNA - Network Basics

CCNA

Cisco Certified Network Associate 

Introduction to Networking and Network Basics :

It is important to understand what a network is and the importance of networks themselves. Every host has a Network Interface Card (NIC) that is used to connect it to a network.

A hub is a network device that repeats information received from a host to all other connects hosts. The hub will relay any information received from Host A to Host B and Host C. This means that all the three hosts can communicate with each other. Communication between hosts can be classified into three types:

Unicast – Communication from one host to another host only.

Broadcast – Communication from one host to all the hosts in the network.

Multicast – Communication from one host to few hosts only.

When a hub is used to network hosts, there are two problems that arise:

A hub repeats information received from one host to all the other hosts. To understand this, consider Host A sending a unicast message to Host B. When the hub receives this message; it will relay the message to both Host B and Host C. Even though the message was a unicast intended only for Host B, Host C also receives it. It is up to Host C to read the message and discard it after seeing that the message was not intended for it.

A hub creates a shared network medium where only a single host can send packets at a time. If another host attempts to send packets at the same time, a collision will occur. Then each device will need to resend their packets and hope not to have a collision again. This shared network medium is called a single collision domain. Imagine the impact of having a single collision domain where 50 or 100 hosts are connected to hubs that are interconnected and they are all trying to send data. That is just a recipe for many collisions and an inefficient network.

The problems associated with hubs can cause severe degradation of a network. To overcome these, switches are used instead of hubs. Like hubs, switches are used to connect hosts in a network but switches break up collision domain by providing a single collision domain for every port. This means that every host (one host connects to one port on the switch) gets its own collision domain thereby eliminating the collisions in the network. With switches, each host can transmit data anytime. Switches simply “switch” the data from one port to another in the switched network. Also, unlike hubs, switches do not flood every packet out all ports. They switch a unicast packet to the port where the destination host resides.

Now that you know how a switch works and improves a network, consider the one problem associated with a switched network. Earlier, you learned that hubs flood out all packets, even the unicast ones. A switch does not flood out unicast packets but it does flood out a broadcast packet. All hosts connected to a switched network are said to be in the same broadcast domain. All hosts connected to it will receive any broadcast sent out in this domain. While broadcasts are useful and essential for network operations, in a large switched network too many broadcasts will slow down the network. To remedy this situation, networks are broken into smaller sizes and these separate networks are interconnected using routers. Routers do not allow broadcasts to be transmitted across different networks it interconnects and hence effectively breaks up a broadcast domain.

Mac Address - 12 digit unique value.

IP Address use to find the particular host in the network, it can be considered as 2 values, bit Network bit and Host bit.

IP Address rule for same network:

-              Network bit need to be same

-             Host bit need to be different.

Microsoft Outlook Tips!!!!

Repair Outlook Data Files (.pst and .ost) for Outlook 2010

1.       Open Windows Explorer and select the drive:\Program Files\Microsoft Office\OFFICE14 folder.

2.       Double-click Scanpst.exe.

3.       In the Enter the name of the file you want to scan box, enter the name of the .pst or .ost file that you want to check, or click Browse to select the file.

4.       To specify the scan log options, click Options, and then click the option that you want.

5.       Click Start.

If errors are found, you are prompted to start the repair process to fix the errors.

A backup file is created during the repair process. To change the default name or location of this backup file, in the Enter name of backup file box, enter a new name, or click Browse to select the file that you want to use.

6.       Click Repair.

Start Outlook with the profile that contains the .pst file that you tried to repair.

How to save Outlook messages in PDF format

If you already have PDF printer /Adobe Acrobat software, skip to step 3.

Download and install PDF printer / Adobe Acrobat.

Select the Outlook messages you would like to have converted to PDF.

Click the Message Save Outlook toolbar button. Check the "Print" option.

Click "Save Now"

The messages will be converted to PDF according to your PDF printer settings.

Creating Rules to Manage Your Email

Click File -> Info , and then the Manage Rules & Alerts button.

Click New Rule... on the Email Rules tab. The Rules Wizard dialog will pop up

Rules & Alerts :  Select a template, choose the template that most closely resembles the action you would like to take. Ensure you select a template from the Stay Organized or Stay Up to Date sections

Rules Wizard: Edit the rule description, click on the underlined text in order to specify the details of your rule (e.g. move messages from Office Watch mailing list into the Newsletters folder). Check carefully to make sure that the details are correct and complete. Click Next

Select any additional criteria you would like to set , Select condition(s) by clicking on the underlined words and adding in your criteria.

Specify the details for those criteria in the Edit the rule description box (optional)

Type a name for the rule in the box for  Specify a name for this rule

Tick the box next to Run this rule now... if you want to apply the rule to messages already received

 When you are certain of the details of the rule and want to commit to it, click Finish

Your rule will now appear listed, with a description of the settings, in the Rules and Alerts dialog box

Password on pst-file

To set a password on your pst-file, you must bring up the Properties dialog of the pst-file in Outlook.

 Outlook 2003 and Outlook 2007
          File-> Data File Management…-> double click on your data file-> button: Change Password…

 Outlook 2010 and Outlook 2013
          File-> Account Settings-> Account Settings…-> tab Data Files-> double click on your data file-> button: Change Password…

Leave the “Old password” field empty when no password has been set yet.

Windows Commands

Windows Commands 

There are some things you can only do from the command line, even some commands that remain useful

Serial number and Machine type:

The following commands can be used to retrieve Serial number and machine type from Windows command prompt.

Machine Serial Number:

C:\> wmic bios get serialnumber

Machine Type:

C:\> wmic csproduct get name

Ipconfig

This command relays the IP address that your computer is currently using. However, if you’re behind a router (like most computers today), you’ll instead receive the local network address of the router.

Still, ipconfig is useful because of its extensions. “ipconfig /release” followed by “ipconfig /renew” can force your Windows PC into asking for a new IP address.

Netstat

Entering the command “netstat -an” will provide you with a list of currently open ports and related IP Address.

Ping

Typing “ping” followed by an IP address or web domain will send a series of test packets to the specified address

Pathping

This is a more advanced version of ping that’s useful if there are multiple routers between your PC and the device you’re testing. Like ping, you use this command by typing “pathping” followed by the IP address.

Tracert

The “tracert” command is similar to pathping. Once again, type “tracert” followed by the IP address or domain you’d like to trace. You’ll receive information about each step in the route between your PC and the target.

Powercfg

Powercfg is a very powerful command for managing and tracking how your computer uses energy. You can use the command “powercfg /hibernate on” and “powercfg /hibernate off” to manage hibernation, and you can also use the command “powercfg /a” to view the power-saving states currently available on your PC.

Shutdown

This command can also be used to restart your computer. On Windows 8, you can even use a special switch to restart your computer into the advanced startup options menu.

·         Shut Down: shutdown /s /t 0

·         Restart: shutdown /r /t 0

·         Restart Into Startup Options: shutdown /r /o

System File Checker

System File Checker is an automatic scan and repair tool that focuses on Windows system files.

Tasklist

The “tasklist” command can be used to provide a current list of all tasks running on your PC. 

Taskkill

Tasks that appear in the “tasklist” command will have an executable and process ID (a four-digit number) associated with them. 

  

Telnet – Connect to Telnet Servers

The telnet client isn’t installed by default. You’ll have to install it from the Control Panel. Once installed, you can use the telnet command to connect to telnet servers without installing any third-party software.

cipher – Permanently Delete and Overwrite a Directory

ciper /w:C:\

Map Network Drive & Script

How to Map a Network Drive

On the Start menu, click Computer.

In the next window, click Map Network Drive.

In the Folder box, type the path to the server name or IP address and Folder name and then click Finish. e g: \\192.168.1.5\Foldername

If Connecting Using Different Credentials. In the User name box, type your user name for the domain and password. (The domain will be different for different servers. It may be displayed under the Password box)

In the Password box, type your password for the domain, and then click OK.

Map Network Drive using Command:

The command NET USE allows you to setup a mapped network drive and follows this syntax

Open Notepad,

                  net use Z: \\server name or IP Address\ File

To Delete a Mapped Drive use the following syntax

               net use Y: /Delete

               net use Z: /Delete

Save the notepad file as (File name) .bat

Hard Drive -Bad Sectors

Why Hard Drives Get Bad Sectors?

A bad sector on a hard drive is simply a tiny cluster of storage space — a  sector — of the hard drive that appears to be defective. The sector won’t respond to read or write requests.

Bad sectors can occur on both traditional magnetic hard drives and modern solid-state drives. There are two types of bad sectors — one resulting from physical damage that can’t be repaired, and one resulting from software errors that can be fixed.

Types of Bad Sectors

There are two types of bad sectors — often divided into “physical” and “logical” bad sectors or “hard” and “soft” bad sectors.

1.    A physical bad sector is a cluster of storage on the hard drive that’s physically damaged.

2.    A logical bad sector is a cluster of storage on the hard drive that appears to not be working properly. Soft bad sectors are caused by software issues. Viruses and other malware that messes with your computer could also cause such system issues and cause soft bad sectors to develop

How to Check for and Repair Bad Sectors

Windows has a built-in Disk Check tool — also known as chkdsk

Other operating systems, including Linux and OS X, also have their own built-in disk utilities for detecting bad sectors. Bad sectors are just a reality of hard disks, and there’s generally no reason to panic when you encounter one. However, you should always have backups of your important files just in case a freak bad sector strikes — and rapidly developing bad sectors can certainly suggest oncoming hard drive failure.

Close all of your open programs and files. Windows 7 can't scan or fix a bad sector if that sector is being used by an open program or file