Netmiko tested script for show version output | Network Automation | Python |

 from netmiko import ConnectHandler

cisco = {

  'device_type': 'cisco_ios',

  'host': '1.1.1.1', 

  'username': 'test', 

  'password': 'test',

  }

  

print("*****SSH Connection created succussfully*****")

net_connect = ConnectHandler(**cisco)

output = net_connect.send_command("sh ver")

print(output)

Top 10 Network Troubleshooting Tools

Hi Networkers,

Today I have something special for you if you are from IT background or working as a Network Engineer / System Engineer then this blog is going to very helpful.
In this blog I came up with 10 very helpful Network tools which will help you to troubleshoot Network issues.

 
1-NMAP:

Nmap is very use full tool to discover open ports, operating system version and many more.

Download : Click here
 

2- Wireshark:

Wireshark is very helpful tool for Network engineer/Network Security Engineer and the hackers to capturing/analyzing  the  the packet.

Download

3-Speedtest.net/pingtest.net


This is a website which is used to test your network bandwidh.

Website  Speedtest

Website PingTest


4-Subnet and IP Calculator



This website is very helpful for subnetting design and IP addressing schema design.

Website


5-PuTTY/Tera Term

Used to access Network devices and the Unix and Linux servers.

Putty Download Page 

6-Netstat


This is very important command to check the active ports or connection in the server or client.

7-Nslookup


This command is used to check DNS lookup.If you have the IP address of any server or client and you want to know the host name then you can use this command.

8-Ipconfig/ifconfig


IPconfig is a windows command to check the IP , SUBNET MASK , GATWAY,DNS etc details.
ifconfig is Linux based command  to check IP , SUBNET MASK , GATWAY,DNS etc details.


9-Tracert/traceroute


To trace the connectivity and to  check how to is the destination devices.


10-Ping.

The most commonly used network tool is the ping utility.

Top 7 Network Monitoring Tools | NMS TOOLS |

Here are 7 best network monitoring tools following below.

1- SolarWinds Network Performance Monitor.

Network Performance Monitor helps you reduce network outages and quickly detect, diagnose, and resolve multi-vendor network performance issues.

• Advanced network troubleshooting for on-premises, hybrid, and cloud services
• Multi-vendor monitoring that scales and expands with the needs of your network
• Availability, real-time, and historical statistics from SNMP, API, or WMI enabled devices

Website: Click here


 

2- ManageEngine OpManager

Most IT shops use multiple network monitoring tools to monitor and manage network operations. However, in case of any fault, they have to sift through multiple tools, GUI, graphs, and reports to get to the bottom of the issue. ManageEngine OpManager, the integrated network management software, provides real-time network monitoring and offers detailed insights into various problematic areas of the network. It also allows you to easily drill down to the root cause of the network issue and fix it quickly.


Website: Click here


3-  NetCrunch

Website: https://www.adremsoft.com 




4- PRTG Network Monitor

Website : Click here


5- Nagios

Website : Click here


6- Zabbix

Website: Click here


7- LogicMonitor.

Website : Click here

Layer 3 Switch vs Router | Difference between layer 3 switch and Router |

Layer 3  Switch vs Router |  Difference between layer 3 switch and Router |

1- L3 Switch do switching at layer 3 by preserving the source and destination mac and preserving the TTL value of the IP header of the 1st routed packet, so the first packet is routed using normal routing lookup, but after that all packet are switched.

2- router do normal routing lookup, but by introducing fast switching and CEF, packets are also now switched on a router.

3- Switches doesnt support some QoS features.

4- Switches doesnt support NAT.

5- The forwarding on switches is done on ASIC (Application Specific Integrated Circuits) which is done in hardware rather than a software.

6- Forwarding on routers are done in a software.

7- router supports different WAN technologies (modules) unlike switches.

IP PROTOCOL No

IP v4 Packet Information

■ Version: This field is 4 bits in length. It indicates the IP header’s format, based on the

version number. Version 4 is the current version; therefore, this field is set to 0100 (4 in

binary) for IPv4 packets. This field is set to 0110 (6 in binary) in IPv6 networks.

■ IHL (Internet Header Length): This field is 4 bits in length. It indicates the length of the

header in 32-bit words (4 bytes) so that the beginning of the data can be found in the IP

header. The minimum value for a valid header (five 32-bit words) is 5 (0101).

ToS (Type of Service): This field is 8 bits in length. Quality of service (QoS) parameters

such as IP precedence or DSCP are found in this field.

■ Total Length: This field is 16 bits in length. It represents the length of the datagram or

packet in bytes, including the header and data. The maximum length of an IP packet can

be 216 − 1 = 65,535 bytes. Routers use this field to determine whether fragmentation is

necessary by comparing the total length with the outgoing MTU.

■ Identification: This field is 16 bits in length. It identifies fragments for reassembly.

■ Flags: This field is 3 bits in length. It indicates whether the packet can be fragmented

and whether more fragments follow. Bit 0 is reserved and set to 0. Bit 1 indicates

May Fragment (0) or Do Not Fragment (1). Bit 2 indicates Last Fragment (0) or More

Fragments to Follow (1).

■ Fragment Offset: This field is 13 bits in length. It indicates (in bytes) where in the packet

this fragment belongs. The first fragment has an offset of 0.

■ Time to Live: This field is 8 bits in length. It indicates the maximum time the packet is to

remain on the network. Each router decrements this field by 1 for loop avoidance. If this

field is 0, the packet must be discarded. This scheme permits routers to discard undeliverable

packets.

■ Protocol: This field is 8 bits in length. It indicates the upper-layer protocol. The Internet

Assigned Numbers Authority (IANA) is responsible for assigning IP protocol values.

■ Header Checksum: This field is 16 bits in length. The checksum does not include the

data portion of the packet in the calculation. The checksum is recomputed and verified

at each point the IP header is processed.

■ Source Address: This field is 32 bits in length. It is the sender’s IP address.

■ Destination Address: This field is 32 bits in length. It is the receiver’s IP address.

■ IP Options: This field is variable in length. The options provide for control functions

that are useful in some situations but unnecessary for the most common communications.

Specific options are security, loose source routing, strict source routing, record

route, and timestamp.

■ Padding: This field is variable in length. It ensures that the IP header ends on a 32-bit

boundary.

How SSH works?

How SSH Works?

The SSH connection is implemented using a client-server model. To establish a connection the server should be running and clients generally authenticated either using passwords or SSH keys. Password Authentication is simple and straightforward. To authenticate using SSH keys, a user must have an SSH key pair (Public and Private key). On the remote server, the list of public keys is maintained (usually) in the ~/.ssh/authorized_keys directory. When the client connects to the remote server using the public key, the server checks for it and sends an encrypted message which can only be decrypted with the associated private key at the client side. We will be using a Python module called Paramiko. The Paramiko module gives an abstraction of the SSHv2 protocol with both the client side and server side functionality. As a client, you can authenticate yourself using a password or key and as a server, you can decide which users are allowed access and the channels you allow.

NAT Interview Questions

OSPF Interview Questions

ACL Interview Questions