Get all IP addresses in a range in PHP

Question

I have 900+ IP address ranges from the Microsoft Azure datacentres (http://www.microsoft.com/en-us/download/confirmation.aspx?id=41653) and I want to find out if an IP address is coming from one of these addresses. I've converted it into a single list which could be stored in a text file.

So: is it more costly to loop through each address and use ip2long() such as point 3 here (https://mebsd.com/coding-snipits/php-ipcalc-coding-subnets-ip-addresses.html) OR is it better to convert all IP addresses in the range, store them in a database and then look them up? If the latter, how does one achieve this (i.e. convert a range to all IP addresses within it)?

The key for me is that it must be fast as we'll be checking this fairly often.

Example IP addresses/ranges:

40.112.124.0/24
65.52.128.0/19
94.245.97.0/24
104.47.169.0/24
104.214.240.0/24
137.116.192.0/19
157.55.8.96/27
157.55.8.128/27
157.55.8.160/28
168.63.0.0/19

Put it in a database as ints then use `between`. Something like `where IP between rangestart and rangeend`. — chris85, Sep 22 '15 at 15:22
No, that would be a column name. That is a SQL query, for DB. — chris85, Sep 22 '15 at 15:25
Ok, so how do you convert each IP to their rangeend? I.e. 157.55.8.96/27? Plus is that the cheapest way? — Ukuser32, Sep 22 '15 at 15:27
is it a contiguous netblock or disparate ips from different net ranges? — Professor Abronsius, Sep 22 '15 at 15:28
Ok, several netblocks - you might find this useful, at least it would cut down the need to process 900+ individual ip addresses... http://stackoverflow.com/questions/594112/matching-an-ip-to-a-cidr-mask-in-php5 — Professor Abronsius, Sep 22 '15 at 15:30

BareNakedCoder · Accepted Answer · 2015-09-22T21:04:29.623

Wow, there's almost 1000 IP ranges in the list! To optimize verifying a single IP address is in one of the IP ranges, you definitely should do some pre-processing of the IP range list. Creating a database is one way. I'd look at SQLite as it is a super-fast local file format that can be faster for read-only tasks like this than sending a query to another process (or machine) running a database.

Create a table with columns "range_start" and "range_end" and indexes on these columns. For each IP address range, insert one row with the start and end of the range. You'll have less than 1000 rows when done. Now, to test an IP address ...

SELECT * FROM IP_RANGES WHERE $testIP>=range_start AND $testIP<=range_end

(modify this SQL statement to match how you're calling the database, preferably with PDO, and preferably in an SQL-injection safe way).

UPDATE: Sorry, missed the comments above while I was typing my answer.

@Ukuser32, yes, use ip2long to convert dotted decimal to long ints (much easier to work with; store long ints in the database). To get the end of the range, look at the 2nd part of the CIDR. It is the number (N) of bits, starting from the left, that are fixed within the range. That means 32-N is the number of variable bits. Which means there are 2**(32-N) ips in the range. Which means $range_end can be calculated ...

list($range_start, $range_end) = cidr2range('40.112.124.0/24');
echo "Start: $range_start, end: $range_end\n";

function cidr2range($cidr) {
    $cidr = explode('/', $cidr);
    $range_start = ip2long($cidr[0]);
    $range_end = $range_start + pow(2, 32-intval($cidr[1])) - 1;
    return [$range_start, $range_end];
}

I'm assuming the function in http://stackoverflow.com/questions/594112 would allow me to convert the final IP address from the range? If not how would I do that? I'm off now but will respond tomorrow :) — Ukuser32, Sep 22 '15 at 15:49

Get all IP addresses in a range in PHP

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