About Me
CompTIA Linux+
1 Introduction to Linux
1-1 History and Evolution of Linux
1-2 Linux Distributions
1-3 Open Source Software
1-4 Linux Community and Support
2 Linux Installation and Configuration
2-1 Planning for Installation
2-2 Installation Methods
2-3 Partitioning Schemes
2-4 Boot Loaders
2-5 Post-Installation Tasks
2-6 System Updates and Patches
3 Linux Command Line Basics
3-1 Shell Overview
3-2 Navigation Commands
3-3 File and Directory Management
3-4 Text Manipulation Commands
3-5 File Permissions and Ownership
3-6 Process Management
3-7 Package Management
4 User and Group Management
4-1 User Account Management
4-2 Group Management
4-3 Password Policies
4-4 User and Group Configuration Files
4-5 User and Group Permissions
5 File Systems and Storage Management
5-1 File System Types
5-2 File System Creation and Management
5-3 Disk Partitioning
5-4 Logical Volume Management (LVM)
5-5 RAID Configuration
5-6 Storage Solutions
6 Networking Fundamentals
6-1 Network Configuration
6-2 Network Services
6-3 Network Troubleshooting
6-4 Network Security
6-5 Network Configuration Files
7 System Services and Daemons
7-1 Service Management
7-2 System Logging
7-3 Cron Jobs
7-4 System Monitoring
7-5 System Startup and Shutdown
8 Security and Compliance
8-1 Security Best Practices
8-2 Firewall Configuration
8-3 Intrusion Detection Systems
8-4 Security Auditing
8-5 Compliance and Regulatory Requirements
9 Troubleshooting and Maintenance
9-1 System Diagnostics
9-2 Troubleshooting Techniques
9-3 Backup and Restore
9-4 Disaster Recovery
9-5 Performance Tuning
10 Virtualization and Cloud Computing
10-1 Virtualization Concepts
10-2 Virtual Machine Management
10-3 Cloud Computing Basics
10-4 Cloud Service Models
10-5 Cloud Deployment Models
11 Scripting and Automation
11-1 Shell Scripting Basics
11-2 Automation Tools
11-3 Configuration Management
11-4 Task Automation
11-5 Scripting Best Practices
12 Advanced Topics
12-1 Kernel Management
12-2 System Performance Optimization
12-3 High Availability and Load Balancing
12-4 Advanced Networking Concepts
12-5 Linux in Enterprise Environments
Network Troubleshooting Explained

Network Troubleshooting Explained

Key Concepts

Ping

Ping is a basic network utility used to test the reachability of a host on an Internet Protocol (IP) network. It measures the round-trip time for messages sent from the originating host to a destination computer and back. Ping uses the ICMP (Internet Control Message Protocol) echo request and echo reply messages.

Example: If you want to check if your computer can communicate with a website, you can use the command ping www.example.com. This will send packets to the website and wait for a response, showing you the time it took for the packets to travel to the website and back.

Traceroute

Traceroute is a network diagnostic tool used to display the path and measure transit delays of packets across an IP network. It works by sending packets with increasing Time to Live (TTL) values, which causes routers along the path to send back ICMP "Time Exceeded" messages.

Example: To trace the route from your computer to a remote server, you can use the command traceroute www.example.com. This will show you each hop (router) that the packets pass through on their way to the destination.

Netstat

Netstat is a command-line tool that displays network connections for Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and Internet Protocol (IP). It also shows routing tables, interface statistics, masquerade connections, and multicast memberships.

Example: To view all active TCP connections on your computer, you can use the command netstat -t. This will list all the TCP connections, including the local and remote addresses, and the state of the connection.

Nmap

Nmap (Network Mapper) is a free and open-source tool for network discovery and security auditing. It is used to discover hosts and services on a computer network by sending packets and analyzing the responses.

Example: To scan a network for all active hosts, you can use the command nmap -sn 192.168.1.0/24. This will send packets to each IP address in the range and report which hosts are up and running.

Wireshark

Wireshark is a network protocol analyzer that lets you capture and interactively browse the traffic running on a computer network. It provides detailed information about each packet, including the source and destination addresses, protocol used, and payload data.

Example: To capture and analyze network traffic on your local network interface, you can open Wireshark, select your network interface, and start capturing. You can then filter the traffic to view only HTTP packets to analyze web traffic.

SSH

SSH (Secure Shell) is a cryptographic network protocol for operating network services securely over an unsecured network. It is commonly used to log into a remote machine and execute commands, as well as to transfer files using protocols like SFTP.

Example: To connect to a remote server using SSH, you can use the command ssh username@server_ip. This will establish a secure connection to the remote server, allowing you to execute commands and manage files as if you were directly logged into the server.

© 2024 Ahmed Baheeg Khorshid. All rights reserved.