The iptables utility is common across Linux distributions (it's just a way to manipulate the Netfilter functionality in the kernel, which actually does the firewalling). Do you happen to remember the name of the GUI front-end that you used with CentOS (there are several)? If so, try to look for it in the Debian repos with:
Code:
apt-cache search <name>
Once you have foubd the package, you can install it with:
Code:
apt-get install <packagename>