iptables not being saved. have to reboot and reënter rules each 15 minuts

Hi,

I have installed lamp on a vmware host.

Everytime i reboot or after a certain amount of time 10-15 minutes, I get disconnected from my ssh. 

Only thing i can do then is reënter the iptables config.

How can i fix this?

(when i boot up i have to enter the commands to).

Thnx in advance