All the following commands must be run on your voip server.

1.Installation

• First install perl dependencies with cpan :

cpan
install LWP::UserAgent
install Asterisk::AGI
install Time::Piece::MySQL 
install DBI
install Params::Classify

• Copy script to /var/lib/asterisk/agi-bin

cp *.agi /var/lib/asterisk/agi-bin

chown asterisk sugarlookup.agi

chgrp asterisk sugarlookup.agi

chmod +x sugarlookup.agi

• Edit /etc/asterisk/extensions_custom.conf

In [from-sip-external] context add this lines

exten => _.,n,Goto(s,1)
.....
exten => s,1,NoOp(Sugarlookup started)
exten => s,2,AGI(sugarlookup.agi)
exten => s,3,Ringing
...

• Add a new user in your mysql database (crm server)

Go into yousugarcrm.server.com/phpmyadmin

->Privileges ->Add new user

Name : voip
Pwd : ulaval
HOST : youroip.server.com 

2.Configuration

Edit the script and change the following variables :

vim /var/lib/asterisk/agi-bin/SugarlookupCID.agi

$database_hostname = "yoursugarcrm.server.com";
$database_name = "sugarcrm"; 
$database_user = "voip"; 
$database_password = "password"; 

This database user must be authorized to access to you crm database with this ip (the host filed of this user must be the ip of your voip server).