chap的认证过程和一般的认证不相同,要求双方配置分别为:
ppp chap hostname 可以设置也可以不设置(用系统的hostname), username 必需设置为对方的 ppp chap hostname(或对方hostname ) ,双方的密码(共享密钥)必需相同。通过下面的认证过程解析就能分析出为什么可以这样设置。
Router 1:
 hostname r1 
 ! 
 username r2 password 0 cisco 
! -- Hostname of other router and shared secret
 ! 
 interface BRI0/0 
  ip address 20.1.1.1 255.255.255.0 
  no ip directed-broadcast 
  encapsulation ppp 
  dialer map ip 20.1.1.2 name r2 broadcast 5772222 
  dialer-group 1 
  isdn switch-type basic-5ess 
  ppp authentication chap callin 
! -- Authentication on incoming calls only
!收到Challenge包可视为需要Authentication
  ppp chap hostname alias-r1 
! -- Alternate CHAP hostname
 ! 
 access-list 101 permit ip any any 
 dialer-list 1 protocol ip list 101 
 !
Router 2:
 hostname r2
 ! 
 username alias-r1 password 0 cisco 
! -- Alternate CHAP hostname and shared secret.
 ! -- The username must match the one in the ppp chap hostname 
 ! -- command on the remote router.
 !
 interface BRI0/0 
  ip address 20.1.1.2 255.255.255.0 
  no ip directed-broadcast
  encapsulation ppp 
  dialer map ip 20.1.1.1 name 
  alias-r1 broadcast 5771111
! -- Dialer map name matches alternate hostname "alias-r1".
  dialer-group 1 
  isdn switch-type basic-5ess 
  ppp authentication chap
 ! 
 access-list 101 permit ip any any 
 dialer-list 1 protocol ip list 101 
 !
