Fazil Malik

What is VPN? Virtual Private Network (VPN) creates a secure network connection over a public network such as the internet. It allows devices to exchange data through a secure virtual tunnel. It uses a combination of security features like encryption, authentication, tunneling protocols, and data integrity to provide secure communication between participating peers. What is Authentication, Confidentiality & Integrity? Authentication - Verifies that the packet received is actually from the claimed sender. It verifies the authenticity of sender. Pre-shared Key, Digital Certificate are some methods that can be used for authentication. Integrity - Ensures that the contents of the packet has not been altered in between by man-in-middle. Hashing Algorithm includes MD5, SHA. Confidentiality - Encrypts the message content through encryption so that data is not disclosed to unauthorized parties. Encryption algorithms include DES (Data Encryption Standard), 3DES (Triple-DES), AES (Ad...

What is a Firewall? Firewall is a device that is placed between a trusted and an untrusted network. It deny or permit traffic that enters or leaves network based on pre-configured policies. Firewalls protect inside networks from unauthorized access by users on an outside network. A firewall can also protect inside networks from each other. For example - By keeping a Management network separate from a user network. What is the difference between Gateway and Firewall? A Gateway joins two networks together and a network firewall protects a network against unauthorized incoming or outgoing access. Network firewalls may be hardware devices or software programs. Firewalls works at which Layers? Firewalls work at layer 3, 4 & 7. What is the difference between Stateful & Stateless Firewall? Stateful firewall - A Stateful firewall is aware of the connections that pass through it. It adds and maintains information about users connections in state table...

What is FW Monitor? Check Point's FW Monitor is a powerful built-in tool for capturing network traffic at the packet level. The FW Monitor utility captures network packets at multiple capture points along the FireWall inspection chains. These captured packets can be inspected later using the WireShark. What is HSRP Cisco? In computer networking, the Hot Standby Router Protocol (HSRP) is a Ciscoproprietary redundancy protocol for establishing a fault-tolerant default gateway How does HSRP work? “HSRP is a redundancy protocol developed by Cisco to provide gateway redundancy without any additional configuration on the end devices in the subnet. With HSRP configured between a set of routers, they work in concert to present the appearance of a single virtual router to the hosts on the LAN. What is the trace route? Traceroute is a utility that records the route (the specific gateway computers at each hop) through the Internet between your computer and a specified desti...

ARP Message Format Address resolution using  ARP  is accomplished through the  exchange of messages  between the source device seeking to perform the resolution, and the destination device that responds to it. As with other protocols, a special  message format  is used containing the information required for each step of the resolution process. ARP messages use a relatively simple format. It includes a field describing the type of message (its  operational code  or  opcode ) and information on both layer two and layer three addresses. In order to support addresses that may be of varying length, the format specifies the type of protocol used at both layer two and layer three and the length of addresses used at each of these layers. It then includes space for all four of the address combinations we saw in  the previous topic . The format used for ARP messages is described fully in  Table 42 , and illustrated in  Figure 49 ...

If you're planning on pursuing a field in networking or just looking to expand your networking knowledge then this article is for you. TCP/IP utilities are essential -- not only will they help you on your networking exams but you'll be able to diagnose most TCP/IP problems and begin working on solutions. The top 7 tools that I will talk about today include: Ping, Tracert, ARP, Netstat, Nbtstat, NSLookup, and IPconfig. These tools will help you to check the status of your network and allow you to troubleshoot and test connectivity to remote hosts. You use these utilities in Dos and you get there by clicking on  Start , going to  Run  and typing  cmd . Here are the top 7 TCP/IP utilities and their functions. 1. Ping The PING utility tests connectivity between two hosts. PING uses a special protocol called the  Internet Control Message Protocol (ICMP) to determine whether the remote machine (website, server, etc.) can receive the test packet and repl...