![\"\"](\"https:\/\/cdn-images-1.medium.com\/max\/740\/0*mtL_9XmhMIxUV25e.png\")
Topics covers:<\/strong><\/p>\n So, Let get started with first concept subnet masking\/CIDR (Classless Inter-Domain Routing)<\/strong>. As Earlier in part 1 covers What is IP and how this work. I will now tell you how subnet masking\u00a0work.<\/p>\n If you have tested any CIDR or seen the scope of any Hackerone program, it\u00a0has<\/p>\n So, what does this actually\u00a0mean?<\/p>\n here the IP are 32 bits each octet contains 8 bits of number for example above\u00a0is<\/p>\n and in last it has 0\/24 This the first 24 Bits are fixed part of a network and cannot be assign to any device. It only can assign IP such as 123.234.255.X to any device range from 1 to 254 here mostly 1 are your router device and last IP 123.234.255.255 is assigned to broadcast for their\u00a0work.<\/p>\n We can count how many hosts in bits can have for\u00a0example<\/p>\n So, an CIDR with \/24 can have 256 IPs in it, but we have to subtract the network IP and broadcast IP, so it becomes 254 IPs in a\u00a0range.<\/p>\n Same goes with \/16 Here the last 2 octet will change 123.234.X.X this is used for company with many devices as this make a large number of\u00a0IPs.<\/p>\n So how we discover IPs in subnet? We use netdiscover and other tools to discover the host in a particular IP system for\u00a0example<\/p>\n Now it comes to DHCP. It is pool of IPs when a device enters into network DHCP assign the device an IPs from the pool of IPs he has. A device can also set it IP manual but mostly DHCP is used to assign an\u00a0IP.<\/p>\n Here you can assign yourself any IP you want but make sure it is unsued in your network in subnet you have the put the value of your subnet for\u00a0example<\/p>\n You can get it from running ipconfig in your cmd or ifconfig in your\u00a0Linux<\/p>\n Now let\u2019s move on to\u00a0VPN.<\/p>\n VPN (Virtual Private Network) creates a secure encrypted tunnel for data transfer. It changes your public IP to the VPN server\u2019s IP and encrypts your traffic. It helps in connecting to websites without exposing your real\u00a0IP.<\/p>\n OpenVPN is a VPN protocol that uses configuration files (.ovpn) which include details like server address, port, protocol, and certificates to securely connect to a VPN\u00a0server.<\/p>\n Thank you!<\/p>\n Connect with me<\/strong> Join a community of 3,600+ security researchers<\/strong> on our Discord server<\/strong>, where we discuss Web3 vulnerabilities, audits, and much more!<\/strong> 🚀 Network Testing: Core Networking (Foundation) part 3<\/a> was originally published in OSINT Team<\/a> on Medium, where people are continuing the conversation by highlighting and responding to this story.<\/p>","protected":false},"excerpt":{"rendered":" Hi, I am starting a Network testing blog writeups series from basic.So, Let\u2019s get\u00a0started This is part 3 you can get part 2 here Network Testing: Core Networking (Foundation) part\u00a02 credit: centraleyes.com Topics covers: Subnet masking\/CIDR DHCP VPN\/OpenVPN So, Let get started with first concept subnet masking\/CIDR (Classless Inter-Domain Routing). As Earlier in part 1 … Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":480,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-479","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/posts\/479","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/comments?post=479"}],"version-history":[{"count":0,"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/posts\/479\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/media\/480"}],"wp:attachment":[{"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/media?parent=479"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/categories?post=479"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/tags?post=479"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}\n
123.234.255.0\/24 \/\/Random IP<\/pre>\n
123 = 8 Bits
234 = 8 Bits
255 = 8 Bits<\/pre>\nNumber of IPs = 2^(32 - CIDR)
Here CIDR is \/24.
so this will be
IPs = 2^(32-24)
IPs = 2^(8)
IPs= 256<\/pre>\n![\"\"](\"https:\/\/cdn-images-1.medium.com\/max\/716\/1*R_Qr1b3SYDKdRjKUMcZhOQ.png\")
![\"\"](\"https:\/\/cdn-images-1.medium.com\/max\/1024\/1*O3UUXuEmT76IK_Grqu7lfw.png\")
![\"\"](\"https:\/\/cdn-images-1.medium.com\/max\/657\/1*0HvW7sZdDfxrXvR_DCKJNQ.png\")
![\"\"](\"https:\/\/cdn-images-1.medium.com\/max\/608\/1*fQD9BU4EYLWGRq9s5xUq8A.png\")
255.255.255.0<\/pre>\n
![\"\"](\"https:\/\/cdn-images-1.medium.com\/max\/967\/1*bAyh3rskpSTUiZEjeL-M0A.png\")
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