How can I determine the local machine's IP addresses from Perl? - perl

Question

Is there a clean and OS independent way to determine the local machine's IP addresses from Perl?
So far I have found the following solutions:
parse the output of ifconfig and ipconfig (hard, different windows versions have different ipconfig outputs)
establish a network connection to a well-known IP and examine the socket's local IP address (won't work if I can't establish a connection and will determine only one IP address)
Any better suggestion?

Answer 1

Net::Address::IP::Local looks promising.
use Net::Address::IP::Local;
# Get the local system's IP address that is "en route" to "the internet":
my $address = Net::Address::IP::Local->public;

Answer 2

You also have some other options, including your solution to "establish a network connection to a well-known IP and examine the socket's local IP address".
In that case (establishing network connection) however, that article points out that:
there is no such thing as a host's IP address.
Network interfaces have IP addresses, not hosts, and a single network interface can have many (virtual) IP addresses. The operating system's routing subsystem decides which network interface and IP address to use to connect to a remote machine.
If your machine only has one external network interface, and this interface only has one IP address then this IP address is commonly called the machine's address, but that is inaccurate.
For example, if the machine is connected to a VPN via a virtual interface it will use this interface's IP address to connect to another machine on the VPN, not the external IP address
Amongst the other solutions: Sys::Hostname - works if it comes up with a resolvable hostname.
use Sys::Hostname;
use Socket;
my $addr = inet_ntoa((gethostbyname(hostname))[4]);
print "$addr\n";

Answer 3

In my case, I need a solution without any non-core dependencies. I came up with this after studying the code in Net::Address::IP::Local:
#!/usr/bin/env perl
use strict;
use warnings;
use IO::Socket::INET;
my $local_ip_address = get_local_ip_address();
print "$local_ip_address\n";
# This idea was stolen from Net::Address::IP::Local::connected_to()
sub get_local_ip_address {
my $socket = IO::Socket::INET->new(
Proto => 'udp',
PeerAddr => '198.41.0.4', # a.root-servers.net
PeerPort => '53', # DNS
);
# A side-effect of making a socket connection is that our IP address
# is available from the 'sockhost' method
my $local_ip_address = $socket->sockhost;
return $local_ip_address;
}
get_local_ip_address() should return the same string as Net::Address::IP::Local->public_ipv4.
If desired, you can change the PeerAddr attribute (in the arguments to the constructor for IO::Socket::INET) to a local DNS server.

Answer 4

To retrieve the IP address of all interfaces, use IO::Interface::Simple:
perl -MIO::Interface::Simple '-Esay $_->address for grep { $_->is_running && defined $_->address } IO::Interface::Simple->interfaces'
If you are not interested in 127.0.0.1 (loopback) you can filter on $_->is_loopback.

Answer 5

Perldoc has an answer to this question in its FAQ ("perlfaq9") - using different modules (which are parts of the Standard Library) or even a built-in function.

Answer 6

I've had good success with IO::Interface on Linux and Solaris, and I think it even worked on AIX but I can't recall for sure. Poking around on search.cpan.org, rt.cpan.org and ActiveState's various sites, it looks like IO::Interface may be experiencing build problems on Windows. I guess the only way to know if it's available is to search for io-interface in PPM.

Answer 7

use WMI?
Example of extracting IP addresses (in Powershell, but it's pretty clear what's happening)
Example of accessing WMI from Perl (not the same WMI functions, but again the process is reasonably clear)
EDIT: after a search on Google codesearch for Networkadapterconfiguration and language "perl":
Example looks like pretty much what you need
EDIT2: In fact the OCS code seems to contain code for most platforms to do this, so while there may be no one set of code that does this, you may be able to re-use their ideas. It's GPL'd, though.
For example, here's the Solaris code. Other bits cover BSD, Linux, MacOS...

Answer 8

getting a network interface's IP address in Perl without additional modules usage and 'ifconfig' output parsing

Answer 9

Net::Address::IP::Local works fine, but since the original poster asks for all the local addresses, I think this one is better:
http://www.perlmonks.org/?node_id=166951
It worked fine for me with ActivePerl for Windows XP.

Answer 10

for windows I use
foreach (split(/\r?\n/,`netstat -r`))
{
next unless /^\s+0.0.0.0/;
#S = split(/\s+/);
# $S[3] = Default Gateway
# $S[4] = Main IP
}
The first line starting 0.0.0.0 is the default gateway. There maybe multiple gateways.
Lines starting 255.255.255.255 are also useful. netstat -r and route print are the same.
Can be adapted for OSX, Linux not so helpful.

Answer 11

I have used a combination of these Linux commands so no dependancy on any perl module.
hostname -i
hostname -I
ls /sys/class/net
ip -f inet addr show eth0| grep -Po 'inet \K[\d.]+'