拓扑图：
PPP0A：(CPE要执行地址转换)在atm上做
CPE: int f0/0 ip add 192.168.1.1 255.255.255.0 no shut
int atm1/0 no shut
pvc 2/200 encap aal5snap protocol ppp dialer dialer pool-member 1
dialer-list 1 protocol ip permit
int dialer0 创建一个逻辑拨号口 encap ppp ip address negotiated 相当于dhcp(ip address dhcp),地址是协商出来的 ppp chap hostname cisco ppp chap password cisco dialer pool 1 dialer-group 1 定义什么流量引起拨号,这里的1是上面list 1
ip route 0.0.0.0 0.0.0.0 dialer0
access-list 1 permit any ip nat pool cisco 202.1.1.2 202.1.1.10 netmask 255.255.255.0 ip inside source list 1 pool cisco overload
int f0/0 ip nat inside int dialer0 ip nat outside
Client:
int f0/0 ip add 192.168.1.2 255.255.255.0 no shut
ip route 0.0.0.0 0.0.0.0 192.168.1.1
ISP: username cisco password cisco ip local pool cisco 202.1.1.2 202.1.1.10
int virtual-template 1 虚模板相当于一个函数，使用时调用函数 int unnumbered lo0 借环回口的地址 peer default ip address pool cisco ppp authentication chap 我是主认证方
int atm1/0 no shut pvc 1/100 encap aal5snap protocol ppp virtual-template 1