IP Address using PHP not reliable - php

Question

I use a javascript API from (http://www.iplocationtools.com) to give me the location data from a visitors IP. For some reason, their API won't give me the actual IP of the visitor, just the other info, which is why I have to use PHP and CodeIgniter to give me the IP instead.
So I use CodeIgniter/PHP to get the IP of a visitor and add it to the database along with location data from above by using PHP's ip2long([the ip code igniter gives me])
I'm confused when my database table looks like this: http://pulse.media.mit.edu/images/1.png
Which is wrong? I'm tempted to believe CodeIgniter is wrong since it gives me the same IP so many times. Age and sex are self reported and I doubt one person is making up all this information.
At the end of the day, all we really need is the users IP and location, preferably from the same source, so we don't compound errors.
Anybody have a better idea on how to do this?
EDIT: Here is the code that I'm using to get the IP address from CodeIgniter
$data['ip_address'] = ip2long($this->input->ip_address());
$this->pulse_model->voter_info($data);
Then the voter_info function just inserts it into the database where it's stored as an INT(11).
And here is the function ip_address:
function ip_address()
{
if ($this->ip_address !== FALSE)
{
return $this->ip_address;
}
if (config_item('proxy_ips') != '' && $this->server('HTTP_X_FORWARDED_FOR') && $this->server('REMOTE_ADDR'))
{
$proxies = preg_split('/[\s,]/', config_item('proxy_ips'), -1, PREG_SPLIT_NO_EMPTY);
$proxies = is_array($proxies) ? $proxies : array($proxies);
$this->ip_address = in_array($_SERVER['REMOTE_ADDR'], $proxies) ? $_SERVER['HTTP_X_FORWARDED_FOR'] : $_SERVER['REMOTE_ADDR'];
}
elseif ($this->server('REMOTE_ADDR') AND $this->server('HTTP_CLIENT_IP'))
{
$this->ip_address = $_SERVER['HTTP_CLIENT_IP'];
}
elseif ($this->server('REMOTE_ADDR'))
{
$this->ip_address = $_SERVER['REMOTE_ADDR'];
}
elseif ($this->server('HTTP_CLIENT_IP'))
{
$this->ip_address = $_SERVER['HTTP_CLIENT_IP'];
}
elseif ($this->server('HTTP_X_FORWARDED_FOR'))
{
$this->ip_address = $_SERVER['HTTP_X_FORWARDED_FOR'];
}
if ($this->ip_address === FALSE)
{
$this->ip_address = '0.0.0.0';
return $this->ip_address;
}
if (strpos($this->ip_address, ',') !== FALSE)
{
$x = explode(',', $this->ip_address);
$this->ip_address = trim(end($x));
}
if ( ! $this->valid_ip($this->ip_address))
{
$this->ip_address = '0.0.0.0';
}
return $this->ip_address;
}

Answer 1

$_SERVER['REMOTE_ADDR'] is the PHP code to return the IP address of the person viewing the page.

Answer 2

Old versions of ip2long() will return -1 if the IPv4 address is invalid. You may want to use inet_pton instead and expand the field used to hold it to 128 bits.

Answer 3

Based on your code, it looks like $this->input->ip_address() has the possibility of returning '0.0.0.0' if the IP is not valid or could not be determined. However, your comments also state that you need to record the ip address even if the above method returns '0.0.0.0'.
First, I'd recommend checking to see if $this->input->ip_address() and $this->valid_ip() are working as expected. Is $this->valid_ip() returning false for IP's that should be considered valid?
Second, I'd update your code to always fall back to $_SERVER['REMOTE_ADDR'] if $this->input->ip_address() returns '0.0.0.0'.
$ip_address = $this->input->ip_address();
if($ip_address == '0.0.0.0') {
$ip_address = $_SERVER['REMOTE_ADDR'];
}
$data['ip_address'] = ip2long($ip_address);
$this->pulse_model->voter_info($data);
Or if you wanted, you could not use $this->input->ip_address() and do as #rockerest suggests and just use $_SERVER['REMOTE_ADDR'] to being with.
$data['ip_address'] = ip2long($_SERVER['REMOTE_ADDR']);
$this->pulse_model->voter_info($data);