Simple Check questions

[predatorz]

Hi,

Currently i using the below trigger to check the availablility of servers for pop, smtp, ssh, ping, DNS.

Server_name:tcp,53.nodata(300)}=0
Server_name: pop_perf.nodata(300)}=0
Server_name:smtp_perf.nodata(300)}=0
Server_name:ssh_perf.nodata(300)}=0
Server_name:icmpping.nodata(300)}=0

It will return the status as true when it occurs and will not revert status back to false again, when server is online. it will send me an email when it is down, how to i set it so that when the server is back up, it will revert back status to false and notify me via email vice versa

Thanks

Using zabbix 1.1.6 on Fc5