Zabbix 1.8 for debian lenny can be installed from backports. There are available zabbix-server, zabbix-agent and zabbix-frontend-php in repository. This example shows how you can install zabbix-agent.
1. Add this line
deb http://www.backports.org/debian lenny-backports main contrib non-free
to your /etc/apt/sources.list.
apt-get install debian-backports-keyring
apt-get -t lenny-backports install zabbix-agent
Note: When you have ipv6 enabled in kernel, you need define server ipv4 address in agent configuration file /etc/zabbix/zabbix_agentd.conf in form ::ffff:<ipv4 address>
Otherwise, you’ll get connection problem from server.