vpdn enable ! vpdn-group pppoe request-dialin PRotocol pppoe ! interface Ethernet0/0 no ip address full-duplex pppoe enable pppoe-client dial-pool-number 1 ! interface Ethernet0/1 ip address 10.0.0.254 255.255.255.0 ip nat inside ip tcp adjust-mss 1452 full-duplex no cdp enable ! interface Dialer1 mtu 1492 ip address negotiated ip nat outside encapsulation ppp dialer pool 1 dialer-group 2 no cdp enable ppp authentication pap callin ppp pap sent-username fmapdof passWord 0 f535120 ! ip nat inside source list 1 interface Dialer1 overload no ip http server ip classless ip route 0.0.0.0 0.0.0.0 Dialer1 permanent ! access-list 1 permit any dialer-list 2 protocol ip permit ================= 需要注重的就是 ip tcp adjust-mss 1452 调整tcp最大分段大小以满足PPPOE下的MTU 因为pppoe下 实际的数据段只能为1500-8(ppp的头)=1492,1492再减去TCP和IP头各20等于1452,也就是说为了避免2层上不停的分割数据包,适应某些应用如MSN,同时加快传输.
