Debug信息：

*0.182263 Quidway PPP/8/debug2:

         PPP State Change:

      Dialer1:0 IPCP : reqsent --> acksent

*0.182268 Quidway PPP/8/debug2:

      PPP Packet:

      Dialer1:0 Input  IPCP(8021) Pkt, Len 26

      State acksent, code ConfNak(03), id 0, len 22

      Primary DNS Server Address(81), len 6, val dac90403 

      Secondary DNS Server Address(83), len 6, val d38812ab 

      IP Address(3), len 6, val dacf1c68 

*0.182269 Quidway PPP/8/debug2:

  PPP Event:

      Dialer1:0 IPCP RCN(Receive Config Nak/Reject)  Event

      state acksent

*0.182269 Quidway PPP/8/debug2:

  PPP Error:

      Dialer1:0 IPCP : Ipcp_nakci: received wrong NAK!

处理： 在dialer口下配置 

ppp ipcp dns request （配置PPP IPCP主动请求对端的DNS地址）

ppp ipcp dns admit-any （配置路由器可以被动地接收对端分配的DNS地址）