They are not generated by ispconfig, they are generated by the bastille firewall. Bastille firewall is a a well known firewall script that is used to enhance linux security and is around there for > 10 years. Its a very stable and well known software....
http://www.linux.com/archive/feature/118353
Some other rules might be from fail2ban. If you use fail2ban on the same system, you should configure it to use the route command instead of iptables. see ispconfig FAQ for details.