Question

I’m trying to log requests for a script and I want to store the client’s IP Address in an int(4) column, using INET_NTOA() to return it in a readable function.

However, in my Perl CGI script, $ENV{REMOTE_ADDR} contains an IP in host byte order which, when entered into the database with the INET_ATON() function, is converted incorrectly so when I pull it back out, I have a completely different address.

#!usr/bin/perl -wT

use strict; 
use CGI;
use DBI;

my $dbh = DBI->connect("DBI:mysql:$db:$server", "$user", "$password");
my $addr = $ENV{REMOTE_ADDR};

my $insert = $dbh->prepare(qq[insert into access_log (ipaddress) 
                                     values (INET_ATON('$addr'))]);  

$insert->execute or die "sql insert error";

my $retrieve = $dbh->prepare(qq[select INET_NTOA(ipaddress) as IP_Address 
                                from   access_log]);

$retrieve->execute or die "sql select error";
my $newIP = $retrieve->fetchrow_array;

Ideally, this script should return the value of $addr but instead I get something completely different. How can I format $addr before putting it into the database?

Thanks for your help.

Answer 1

I’ve discovered that no change to the $ENV{REMOTE_ADDR} is needed.

By using a an int(4) unsigned for my ip_address column, inet_aton() and inet_ntoa() work correctly. With a signed integer,

“values corresponding to IP addresses for which the first octet is greater than 127 cannot be stored correctly” so the data gets distorted in the insert stage.

http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_inet-ntoa