Problem with PORT 80?!?

[Stephan Hepper]

Hi,
i have this problem:
 see my configuration:
        # Generated by iptables-save v1.2.5 on Wed Feb 27 15:54:45 2002
        *nat
        :PREROUTING ACCEPT [977:52307]
        :POSTROUTING ACCEPT [1101:72522]
        :OUTPUT ACCEPT [1101:72522]
        -A PREROUTING -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3128
        -A POSTROUTING -s 192.168.1.0/255.255.255.0 -o ippp0 -j MASQUERADE
        COMMIT
        # Completed on Wed Feb 27 15:54:45 2002
        # Generated by iptables-save v1.2.5 on Wed Feb 27 15:54:45 2002
        *filter
        :INPUT DROP [0:0]
        :FORWARD DROP [0:0]
        :OUTPUT ACCEPT [88174:99666837]
        :secure-wd - [0:0]
        -A INPUT -i ! ippp0 -p icmp -j ACCEPT
        -A INPUT -p tcp -m tcp --dport 22 -j ACCEPT
        -A INPUT -p udp -m udp --dport 22 -j ACCEPT
        -A INPUT -j secure-wd
        -A FORWARD -j secure-wd
        -A secure-wd -m state --state RELATED,ESTABLISHED -j ACCEPT
        -A secure-wd -i ! ippp0 -m state --state NEW -j ACCEPT
        -A secure-wd -j DROP
        COMMIT
        # Completed on Wed Feb 27 15:54:45 2002


 i do not understand why port 80 is available to ippp0
 if i do a portscan this port is open ?!? why?!?
 if there's anybody how knows please give me a hint...

thanks, hepps