Network Configuration Get Removed After Restarting Zentyal Linux Server

I'm facing a issue with my wireless configuration in Zentyal Linux Server. I configured my wifi network setting in /etc/network/interfaces like this : # interfaces(5) file used by ifup(8) and ifdown(8) auto lo iface lo inet loopback auto wlan1 iface wlan1 inet dhcp wireless-essid wireless-key1 address 192.168.1.100 netmask 255.255.255.0 gateway 192.168.1.1 ... It is working fine but when i restart my Server. Network settings get removed every time and shows following lines only : # interfaces(5) file used by ifup(8) and ifdown(8) auto lo iface lo inet loopback Every time i have to write these settings again to start my wifi. What is going on, and how can I fix this ?