I have several ip addresses like:
115.42.150.37115.42.150.38115.42.150.50What type of regular expression should I write if I want to search for the all the 3 ip addresses? Eg, if I do 115.42.150.* (I will be able to search for all 3 ip addresses)
What I can do now is something like: /[0-9]{1-3}\.[0-9]{1-3}\.[0-9]{1-3}\.[0-9]{1-3}/ but it can't seems to work well.
Thanks.
The regex you've got already has several problems:
Firstly, it contains dots. In regex, a dot means "match any character", where you need to match just an actual dot. For this, you need to escape it, so put a back-slash in front of the dots.
Secondly, but you're matching any three digits in each section. This means you'll match any number between 0 and 999, which obviously contains a lot of invalid IP address numbers.
This can be solved by making the number matching more complex; there are other answers on this site which explain how to do that, but frankly it's not worth the effort -- in my opinion, you'd be much better off splitting the string by the dots, and then just validating the four blocks as numeric integer ranges -- ie:
if(block >= 0 && block <= 255) {....}
Hope that helps.
May be late but, someone could try:
Example of VALID IP address
115.42.150.37
192.168.0.1
110.234.52.124
Example of INVALID IP address
210.110 – must have 4 octets
255 – must have 4 octets
y.y.y.y – only digits are allowed
255.0.0.y – only digits are allowed
666.10.10.20 – octet number must be between [0-255]
4444.11.11.11 – octet number must be between [0-255]
33.3333.33.3 – octet number must be between [0-255]
JavaScript code to validate an IP address
function ValidateIPaddress(ipaddress) {
if (/^(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/.test(ipaddress)) {
return (true)
}
alert("You have entered an invalid IP address!")
return (false)
}
Try this one, it's a shorter version:
^(?!0)(?!.*\.$)((1?\d?\d|25[0-5]|2[0-4]\d)(\.|$)){4}$
Explained:
^ start of string
(?!0) Assume IP cannot start with 0
(?!.*\.$) Make sure string does not end with a dot
(
(
1?\d?\d| A single digit, two digits, or 100-199
25[0-5]| The numbers 250-255
2[0-4]\d The numbers 200-249
)
\.|$ the number must be followed by either a dot or end-of-string - to match the last number
){4} Expect exactly four of these
$ end of string
Unit test for a browser's console:
var rx=/^(?!0)(?!.*\.$)((1?\d?\d|25[0-5]|2[0-4]\d)(\.|$)){4}$/;
var valid=['1.2.3.4','11.11.11.11','123.123.123.123','255.250.249.0','1.12.123.255','127.0.0.1','1.0.0.0'];
var invalid=['0.1.1.1','01.1.1.1','012.1.1.1','1.2.3.4.','1.2.3\n4','1.2.3.4\n','259.0.0.1','123.','1.2.3.4.5','.1.2.3.4','1,2,3,4','1.2.333.4','1.299.3.4'];
valid.forEach(function(s){if (!rx.test(s))console.log('bad valid: '+s);});
invalid.forEach(function(s){if (rx.test(s)) console.log('bad invalid: '+s);});
If you are using nodejs try:
require('net').isIP('10.0.0.1')
doc net.isIP()
Try this one.. Source from here.
"\b(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b"
If you want something more readable than regex for ipv4 in modern browsers you can go with
function checkIsIPV4(entry) {
var blocks = entry.split(".");
if(blocks.length === 4) {
return blocks.every(function(block) {
return parseInt(block,10) >=0 && parseInt(block,10) <= 255;
});
}
return false;
}
Below Solution doesn't accept Padding Zeros
Here is the cleanest way to validate an IP Address, Let's break it down:
Fact: a valid IP Address is has 4 octets, each octets can be a number between 0 - 255
Breakdown of Regex that matches any value between 0 - 255
25[0-5] matches 250 - 2552[0-4][0-9] matches 200 - 2491[0-9][0-9] matches 100 - 199[1-9][0-9]? matches 1 - 990 matches 0const octet = '(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]?|0)';
Notes: When using new RegExp you should use \\. instead of \. since string will get escaped twice.
function isValidIP(str) {
const octet = '(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]?|0)';
const regex = new RegExp(`^${octet}\\.${octet}\\.${octet}\\.${octet}$`);
return regex.test(str);
}
Don't write your own regex or copy paste! You probably won't cover all edge cses (IPv6, but also octal IPs, etc). Use is-ip from npm:
var isIp = require('is-ip');
isIp('192.168.0.1');
Will return a Boolean.
Downvoters: care to explain why using an actively maintained library is better than copy pasting from a website?
My version as es6 method, return true for valid IPs, false otherwise
isIP(ip) {
if (typeof(ip) !== 'string')
return false;
if (!ip.match(/\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}/)) {
return false;
}
return ip.split('.').filter(octect => octect >= 0 && octect <= 255).length === 4;
}
/^(?!.*\.$)((?!0\d)(1?\d?\d|25[0-5]|2[0-4]\d)(\.|$)){4}$/
Full credit to oriadam. I would have commented below his/her answer to suggest the double zero change I made, but I do not have enough reputation here yet...
change:
-(?!0) Because IPv4 addresses starting with zeros ('0.248.42.223') are valid (but not usable)
+(?!0\d) Because IPv4 addresses with leading zeros ('63.14.209.00' and '011.012.013.014') can sometimes be interpreted as octal
Regular expression for the IP address format:
/^(\d\d?)|(1\d\d)|(0\d\d)|(2[0-4]\d)|(2[0-5])\.(\d\d?)|(1\d\d)|(0\d\d)|(2[0-4]\d)|(2[0-5])\.(\d\d?)|(1\d\d)|(0\d\d)|(2[0-4]\d)|(2[0-5])$/;
Throwing in a late contribution:
^(?!\.)((^|\.)([1-9]?\d|1\d\d|2(5[0-5]|[0-4]\d))){4}$
Of the answers I checked, they're either longer or incomplete in their verification. Longer, in my experience, means harder to overlook and therefore more prone to be erroneous. And I like to avoid repeating similar patters, for the same reason.
The main part is, of course, the test for a number - 0 to 255, but also making sure it doesn't allow initial zeroes (except for when it's a single one):
[1-9]?\d|1\d\d|2(5[0-5]|[0-4]\d)
Three alternations - one for sub 100: [1-9]?\d, one for 100-199: 1\d\d and finally 200-255: 2(5[0-5]|[0-4]\d).
This is preceded by a test for start of line or a dot ., and this whole expression is tested for 4 times by the appended {4}.
This complete test for four byte representations is started by testing for start of line followed by a negative look ahead to avoid addresses starting with a .: ^(?!\.), and ended with a test for end of line ($).
See some samples here at regex101.
And instead of
{1-3}
you should put
{1,3}
If you wrtie the proper code you need only this very simple regular expression: /\d{1,3}/
function isIP(ip) {
let arrIp = ip.split(".");
if (arrIp.length !== 4) return "Invalid IP";
let re = /\d{1,3}/;
for (let oct of arrIp) {
if (oct.match(re) === null) return "Invalid IP"
if (Number(oct) < 0 || Number(oct) > 255)
return "Invalid IP";
}
return "Valid IP";
}
But actually you get even simpler code by not using any regular expression at all:
function isIp(ip) {
var arrIp = ip.split(".");
if (arrIp.length !== 4) return "Invalid IP";
for (let oct of arrIp) {
if ( isNaN(oct) || Number(oct) < 0 || Number(oct) > 255)
return "Invalid IP";
}
return "Valid IP";
}
A short RegEx: ^(?:(?:^|\.)(?:2(?:5[0-5]|[0-4]\d)|1?\d?\d)){4}$
Example
const isValidIp = value => (/^(?:(?:^|\.)(?:2(?:5[0-5]|[0-4]\d)|1?\d?\d)){4}$/.test(value) ? true : false);
// valid
console.log("isValidIp('0.0.0.0') ? ", isValidIp('0.0.0.0'));
console.log("isValidIp('115.42.150.37') ? ", isValidIp('115.42.150.37'));
console.log("isValidIp('192.168.0.1') ? ", isValidIp('192.168.0.1'));
console.log("isValidIp('110.234.52.124' ? ", isValidIp('110.234.52.124'));
console.log("isValidIp('115.42.150.37') ? ", isValidIp('115.42.150.37'));
console.log("isValidIp('115.42.150.38') ? ", isValidIp('115.42.150.38'));
console.log("isValidIp('115.42.150.50') ? ", isValidIp('115.42.150.50'));
// Invalid
console.log("isValidIp('210.110') ? ", isValidIp('210.110'));
console.log("isValidIp('255') ? ", isValidIp('255'));
console.log("isValidIp('y.y.y.y' ? ", isValidIp('y.y.y.y'));
console.log(" isValidIp('255.0.0.y') ? ", isValidIp('255.0.0.y'));
console.log("isValidIp('666.10.10.20') ? ", isValidIp('666.10.10.20'));
console.log("isValidIp('4444.11.11.11') ? ", isValidIp('4444.11.11.11'));
console.log("isValidIp('33.3333.33.3') ? ", isValidIp('33.3333.33.3'));\b(?:[0-9]{1,3}\.){3}[0-9]{1,3}\b
matches 0.0.0.0 through 999.999.999.999 use if you know the seachdata does not contain invalid IP addresses
\b(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b
use to match IP numbers with accurracy - each of the 4 numbers is stored into it's own capturing group, so you can access them later
it is maybe better:
function checkIP(ip) {
var x = ip.split("."), x1, x2, x3, x4;
if (x.length == 4) {
x1 = parseInt(x[0], 10);
x2 = parseInt(x[1], 10);
x3 = parseInt(x[2], 10);
x4 = parseInt(x[3], 10);
if (isNaN(x1) || isNaN(x2) || isNaN(x3) || isNaN(x4)) {
return false;
}
if ((x1 >= 0 && x1 <= 255) && (x2 >= 0 && x2 <= 255) && (x3 >= 0 && x3 <= 255) && (x4 >= 0 && x4 <= 255)) {
return true;
}
}
return false;
}
Always looking for variations, seemed to be a repetitive task so how about using forEach!
function checkIP(ip) {
//assume IP is valid to start, once false is found, always false
var test = true;
//uses forEach method to test each block of IPv4 address
ip.split('.').forEach(validateIP4);
if (!test)
alert("Invalid IP4 format\n"+ip)
else
alert("IP4 format correct\n"+ip);
function validateIP4(num, index, arr) {
//returns NaN if not an Int
item = parseInt(num, 10);
//test validates Int, 0-255 range and 4 bytes of address
// && test; at end required because this function called for each block
test = !isNaN(item) && !isNaN(num) && item >=0 && item < 256 && arr.length==4 && test;
}
}
A less stringent when testing the type not the validity. For example when sorting columns use this check to see which sort to use.
export const isIpAddress = (ipAddress) =>
/^((\d){1,3}\.){3}(\d){1,3}$/.test(ipAddress)
When checking for validity use this test. An even more stringent test checking that the IP 8-bit numbers are in the range 0-255:
export const isValidIpAddress = (ipAddress) =>
/^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/.test(ipAddress)
