[问题] shorewall的设置问题！！！

[swordas]

swordas@swordas-laptop:~$ sudo shorewall start
[sudo] password for swordas:
Compiling...
Initializing...
Determining Zones...
IPv4 Zones: net
Firewall Zone: fw
Validating interfaces file...
Validating hosts file...
Pre-processing Actions...
Pre-processing /usr/share/shorewall/action.Drop...
Pre-processing /usr/share/shorewall/action.Reject...
Validating Policy file...
Determining Hosts in Zones...
net Zone: eth0:0.0.0.0/0
Deleting user chains...
Compiling /etc/shorewall/routestopped ...
Creating Interface Chains...
Compiling Common Rules
Adding Anti-smurf Rules
Adding rules for DHCP
Compiling TCP Flags checking...
Compiling Kernel Route Filtering...
Compiling Martian Logging...
Compiling IP Forwarding...
Compiling /etc/shorewall/rules...
Compiling Actions...
Compiling /usr/share/shorewall/action.Drop for Chain Drop...
Compiling /usr/share/shorewall/action.Reject for Chain Reject...
Compiling /etc/shorewall/policy...
Compiling Masquerading/SNAT
ERROR: Unknown interface ppp0
Terminated
swordas@swordas-laptop:~$ i


设置完全按照http://wiki.ubuntu.org.cn/index.php?title=ShoreWall%E5%AE%89%E8%A3%85%E8%AE%BE%E7%BD%AE&variant=zh-cn

请高手指点问题出在哪里！！！