{"id":492,"date":"2010-08-17T15:23:35","date_gmt":"1999-01-01T00:00:00","guid":{"rendered":"https:\/\/fir3netwp.gmsrrpobkbd.com\/?p=492"},"modified":"2021-07-27T16:55:16","modified_gmt":"2021-07-27T16:55:16","slug":"ipv4-subnetting-notes","status":"publish","type":"post","link":"https:\/\/www.fir3net.com\/networking\/concepts\/ipv4-subnetting-notes.html","title":{"rendered":"IPv4 Subnetting Notes"},"content":{"rendered":"<p>The other day someone asked me to explain subnetting. It had been a while so I dusted off my CCNA books and attempted to answer his questions. So I thought this would be an ideal time to jot down some notes for future reference.<\/p>\n<p>This isnt a tutorial or guide but just some some notes on how to calulate the different subnetting values (subnet number, number of hosts etc etc).<\/p>\n<p><strong>What is the broadcast address of the network 172.30.233.0 255.255.255.128 ?<\/strong><\/p>\n<ul>\n<li>128 &#8211; 256 = 128<\/li>\n<li>What is the highest number you can make by placing multiple 128`s into 0. None so this is 0.<\/li>\n<li>(0 + 128) &#8211; 1 = 127<\/li>\n<\/ul>\n<p><em>Answer : Broadcast address is 172.30.233.127<\/em><\/p>\n<p><strong>How many subnets and hosts per subnet can you get from the network 172.30.0.0 255.255.255.240 ?<\/strong><\/p>\n<ul>\n<li>172.30 is a class B RFC 1918 address and has a \/12 prefix. So 12 bits of this address we can do nothing with.<\/li>\n<li>The subnet mask is \/28 so this mean we can break the address into the following :<\/li>\n<li>28 bits &#8211; 12 bits\u00a0 = 16 subnet bits<\/li>\n<li>28 bits &#8211; 32 bits = 4 host bits<\/li>\n<\/ul>\n<ul>\n<li>This means that this subnet number will conisist of [12 network ID bits ] [16 subnet bits] [4 host bits]<\/li>\n<li>With the following power of 2`s in mind we can calculate the hosts and subnets :<br \/>\n65536 32768 16384 8192 4096 2048 1024 512 256 128 64 32 16 8 4 2 1<\/li>\n<\/ul>\n<ul>\n<li>Host bits = go along 4 and then an extra 1 (saves adding them up) then minus 2 due to the the broadcast and subnetnet zero bits. This gives us 14<\/li>\n<li>Subnet bits = go along 16 and then 1 extra gives us 65536 subnets.<\/li>\n<\/ul>\n<p><em>Answer : 65536 subnets and 14 hosts per subnet.<\/em><\/p>\n<p><strong>Which subnet does host 172.24.102.208 255.255.255.224 belong to?<\/strong><\/p>\n<ul>\n<li>224 &#8211; 256 = 32<\/li>\n<li>Whats the highest number we can get by placing 32`s into 208 = 192<\/li>\n<\/ul>\n<p><em>Answer : 172.24.102.192.<\/em><\/p>\n<p><strong>What valid host range is the IP address 192.168.126.95\/26 a part of?<\/strong><\/p>\n<ul>\n<li>192 = 256 = 64<\/li>\n<li>Highest number that you can get from placing 64&#8217;s into 95 = 64.<\/li>\n<li>64 = Subnet number<\/li>\n<li>64 + 1 = First host<\/li>\n<li>(64 + 64) &#8211; 1 = Broadcast<\/li>\n<li>(64 + 64) &#8211; 2 = Last host<\/li>\n<\/ul>\n<p><em>Answer : 192.168.126.65-126<\/em><\/p>\n<p><strong>What valid host range is the IP address 172.16.93.193\/20 a part of?<\/strong><\/p>\n<ul>\n<li>240 = 256 -16<\/li>\n<li>Highest number that you can get from placing 16&#8217;s into 93 = 80.<\/li>\n<li>80 = Subnet number<\/li>\n<li>x.x.80.1 = First host<\/li>\n<li>x.x.80.1 (add 16 to 80 and minus 1), and place .254 into the last octect = Last Host<\/li>\n<\/ul>\n<p>Answer: 172.16.80.1 through to 172.16.95.254<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The other day someone asked me to explain subnetting. It had been a while so I dusted off my CCNA books and attempted to answer his questions. So I thought this would be an ideal time to jot down some notes for future reference. This isnt a tutorial or guide but just some some notes &#8230; <a title=\"IPv4 Subnetting Notes\" class=\"read-more\" href=\"https:\/\/www.fir3net.com\/networking\/concepts\/ipv4-subnetting-notes.html\" aria-label=\"Read more about IPv4 Subnetting Notes\">Read more<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[13],"tags":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.5 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>IPv4 Subnetting Notes - Fir3net<\/title>\n<meta name=\"description\" content=\"The other day someone asked me to explain subnetting. 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