Ip Calculator Ip Subnetting

IP Subnetting Calculator

function ipToDec(ipString) { var parts = ipString.split('.'); if (parts.length !== 4) return NaN; var dec = 0; for (var i = 0; i < 4; i++) { var part = parseInt(parts[i], 10); if (isNaN(part) || part 255) return NaN; dec = (dec <>> 0; // Ensure unsigned 32-bit } function decToIp(decInt) { return ((decInt >>> 24) & 0xFF) + '.' + ((decInt >>> 16) & 0xFF) + '.' + ((decInt >>> 8) & 0xFF) + '.' + (decInt & 0xFF); } function cidrToMaskDec(cidr) { if (cidr 32) return NaN; return (0xFFFFFFFF <>> 0; } function maskDecToCidr(maskDec) { if (maskDec === 0) return 0; var cidr = 0; for (var i = 0; i >> (31 – i)) & 1) { cidr++; } else { break; } } return cidr; } function isValidSubnetMask(maskString) { var parts = maskString.split('.'); if (parts.length !== 4) return false; var maskDec = ipToDec(maskString); if (isNaN(maskDec)) return false; // Check if the mask is contiguous (all 1s followed by all 0s) var invertedMask = ~maskDec >>> 0; return ((invertedMask + 1) & invertedMask) === 0; } function calculateSubnet() { var ipAddressStr = document.getElementById("ipAddress").value.trim(); var maskInputStr = document.getElementById("maskInput").value.trim(); var maskType = document.getElementById("maskType").value; var ipDec = ipToDec(ipAddressStr); if (isNaN(ipDec)) { alert("Invalid IP Address format. Please enter a valid IPv4 address (e.g., 192.168.1.100)."); return; } var cidr; var subnetMaskDec; if (maskType === "cidr") { cidr = parseInt(maskInputStr, 10); if (isNaN(cidr) || cidr 32) { alert("Invalid CIDR Prefix. Please enter a number between 0 and 32."); return; } subnetMaskDec = cidrToMaskDec(cidr); } else { // maskType === "mask" if (!isValidSubnetMask(maskInputStr)) { alert("Invalid Subnet Mask format or value. Please enter a valid subnet mask (e.g., 255.255.255.0)."); return; } subnetMaskDec = ipToDec(maskInputStr); cidr = maskDecToCidr(subnetMaskDec); } var networkAddressDec = (ipDec & subnetMaskDec) >>> 0; var broadcastAddressDec = (networkAddressDec | (~subnetMaskDec >>> 0)) >>> 0; var totalHosts = Math.pow(2, (32 – cidr)); var usableHosts = 0; if (cidr < 31) { // For /31 and /32, usable hosts are 0 usableHosts = totalHosts – 2; } else if (cidr === 31) { // /31 has 2 total hosts, 0 usable usableHosts = 0; } else if (cidr === 32) { // /32 has 1 total host, 0 usable usableHosts = 0; } var firstUsableHostDec = (cidr >> 0 : networkAddressDec; var lastUsableHostDec = (cidr >> 0 : broadcastAddressDec; document.getElementById("networkAddress").innerHTML = "Network Address: " + decToIp(networkAddressDec); document.getElementById("broadcastAddress").innerHTML = "Broadcast Address: " + decToIp(broadcastAddressDec); document.getElementById("firstHost").innerHTML = "First Usable Host: " + (cidr < 31 ? decToIp(firstUsableHostDec) : "N/A"); document.getElementById("lastHost").innerHTML = "Last Usable Host: " + (cidr < 31 ? decToIp(lastUsableHostDec) : "N/A"); document.getElementById("totalHosts").innerHTML = "Total Hosts: " + totalHosts; document.getElementById("usableHosts").innerHTML = "Usable Hosts: " + usableHosts; document.getElementById("subnetMask").innerHTML = "Subnet Mask: " + decToIp(subnetMaskDec); document.getElementById("cidrPrefix").innerHTML = "CIDR Prefix: /" + cidr; } // Initial calculation on page load with default values document.addEventListener('DOMContentLoaded', function() { calculateSubnet(); });

Understanding IP Subnetting

IP subnetting is a fundamental concept in computer networking that involves dividing a large network into smaller, more manageable subnetworks. This process helps in efficient allocation of IP addresses, reduces network congestion, and enhances security by isolating network segments.

Why Subnet?

• Efficiency: Prevents wastage of IP addresses by allocating only what's needed for a specific segment.
• Performance: Reduces broadcast traffic within a segment, improving overall network speed.
• Security: Isolates network segments, making it harder for unauthorized access to spread across the entire network.
• Organization: Simplifies network management by creating logical divisions based on departments, locations, or functions.

Key Subnetting Terms:

To effectively use the IP Subnetting Calculator, it's important to understand the following terms:

• IP Address: A unique numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. It's typically represented in dotted-decimal notation (e.g., 192.168.1.100).
• Subnet Mask: A 32-bit number that distinguishes the network portion of an IP address from the host portion. It's also represented in dotted-decimal notation (e.g., 255.255.255.0). The '1's in the mask represent the network portion, and the '0's represent the host portion.
• CIDR Prefix (Classless Inter-Domain Routing): A more flexible method of IP addressing that replaces the traditional class-based system. It's represented by a slash followed by a number (e.g., /24), indicating the number of bits in the IP address that belong to the network portion.
• Network Address: The first address in a subnet, where all host bits are '0'. It identifies the network itself and cannot be assigned to a host.
• Broadcast Address: The last address in a subnet, where all host bits are '1'. It's used to send data to all devices within that specific subnet and cannot be assigned to a host.
• First Usable Host: The first IP address in a subnet that can be assigned to a device. It's always one greater than the network address.
• Last Usable Host: The last IP address in a subnet that can be assigned to a device. It's always one less than the broadcast address.
• Total Hosts: The total number of IP addresses available within a given subnet, including the network and broadcast addresses.
• Usable Hosts: The number of IP addresses within a subnet that can actually be assigned to devices. This is typically the total hosts minus two (for the network and broadcast addresses). Note: For /31 and /32 subnets, the number of usable hosts is 0.

How to Use This Calculator:

1. Enter IP Address: Input any valid IPv4 address (e.g., 192.168.1.100) into the "IP Address" field. This can be any IP within the network you want to analyze.
2. Enter Subnet Mask or CIDR Prefix:
   • If you know the CIDR prefix (e.g., 24 for a /24 network), enter it into the "Subnet Mask / CIDR Prefix" field and select "CIDR Prefix" from the "Input Type" dropdown.
   • If you know the Subnet Mask (e.g., 255.255.255.0), enter it into the "Subnet Mask / CIDR Prefix" field and select "Subnet Mask" from the "Input Type" dropdown.
3. Click "Calculate Subnet": The calculator will instantly display the Network Address, Broadcast Address, First Usable Host, Last Usable Host, Total Hosts, Usable Hosts, the corresponding Subnet Mask, and CIDR Prefix for your input.

Example:

Let's say you have an IP address 172.16.10.50 and a CIDR prefix of /20.

Input:

• IP Address: 172.16.10.50
• Subnet Mask / CIDR Prefix: 20
• Input Type: CIDR Prefix

Output (after calculation):

• Network Address: 172.16.0.0
• Broadcast Address: 172.16.15.255
• First Usable Host: 172.16.0.1
• Last Usable Host: 172.16.15.254
• Total Hosts: 4096
• Usable Hosts: 4094
• Subnet Mask: 255.255.240.0
• CIDR Prefix: /20

This calculator simplifies the complex binary math involved in subnetting, making it an invaluable tool for network administrators, students, and anyone working with IP networks.