多项选择题
A.代理验证 B.强制CHAP验证 C.IPCP重协商 D.LCP重协商
A.tunnel protocol gre B.tunnel gre C.tunnel-protocol gre D.protocol gre
A.keepalive 103 B.keepalive 3 10 C.keepalive-interval 10 D.keepalive-times 3