某局点SR8808-X portal认证idle-cut参数执行下发异常排查经验案例

     现场终端到BRAS设备即SR8808-X设备，终端到路由器跨了三层网络，并且在SR8808-X上终端流量的入接口上起了三层的portal认证。

       现场8808-X上起了3层的portal认证，目前portal认证过程正常，但是idle-cut参数对于部分终端上线后未授权给用户，导致用户始终无法idle-cut下线，部分终端有被授权idle-cut参数的是能正常idle-cut下线的。

       以下面两个认证用户为例：

用户Username: 201263502117@ytu未被授权idle-cut参数：

Basic:

  Current IP address: 10.10.1.90

  Original IP address: 10.10.1.90

  Username: 201263502117@ytu

  User ID: 0x18003e8c

  Acct-Session-ID: 00000007201903121909510006f3bd2080100475

  Access interface: Route-Aggregation1.10

  Service-VLAN/Customer-VLAN: 10/-

  MAC address: 0000-0000-0000

  Domain name: ytu

  VPN instance: N/A

  Status: Online

  Portal server: srun

  Portal authentication method: Layer3

AAA:

  Realtime accounting interval: 720s, retry times: 5

  Idle cut: N/A          //idle-cut参数未被授权

  Session duration: N/A, remaining: N/A

  Remaining traffic: N/A

  Login time: 2019-03-12 19:09:51 UTC

  Online time: 302:47:56

  Accounting-start fail action: Online

  Accounting-update fail action: Online

  Accounting quota-out action: Offline

  DHCP IP pool: N/A

ACL&QoS&Multicast:

  Inbound CAR: N/A

  Outbound CAR: N/A

  Inbound priority: N/A

  Outbound priority: N/A

  ACL number: N/A

  User profile: N/A

  Session group profile: N/A

  Max multicast addresses: 4

  User group: N/A

Flow statistic:

  Uplink   packets/bytes: 252801/23069353

  Downlink packets/bytes: 133346/153905939

用户  Username: 201763503225@ytu有被授权idle-cut参数：

Basic:

  Current IP address: 10.10.1.24

  Original IP address: 10.10.1.24

  Username: 201763503225@ytu

  User ID: 0x180033e0

  Acct-Session-ID: 0000000720190325094251000746812080100475

  Access interface: Route-Aggregation1.10

  Service-VLAN/Customer-VLAN: 10/-

  MAC address: 0000-0000-0000

  Domain name: ytu

  VPN instance: N/A

  Status: Online

  Portal server: srun

  Portal authentication method: Layer3

AAA:

  Realtime accounting interval: 720s, retry times: 5

  Idle cut: 7200 sec, 20480 bytes, direction: Both          //idle-cut参数授权成功

  Session duration: N/A, remaining: N/A

  Remaining traffic: N/A

  Login time: 2019-03-25 09:42:50 UTC

  Online time: 00:14:57

  Accounting-start fail action: Online

  Accounting-update fail action: Online

  Accounting quota-out action: Offline

  DHCP IP pool: N/A

ACL&QoS&Multicast:

  Inbound CAR: N/A

  Outbound CAR: N/A

  Inbound priority: N/A

  Outbound priority: N/A

  ACL number: N/A

  User profile: N/A

  Session group profile: N/A

  Max multicast addresses: 4

  User group: N/A

Flow statistic:

  Uplink   packets/bytes: 5041/671922

  Downlink packets/bytes: 3638/3852587

（1）首先检查配置，配置无误：

在子接口上起了portal认证：

interface Route-Aggregation1.10

ip address 10.10.1.254 255.255.255.0

vlan-type dot1q vid 10

portal enable method layer3

portal bas-ip 192.168.11.10

portal apply web-server srun

（2）检查设备上认证域的参数生效情况如下：  

现场客户登陆认证使用的认证域为ytu，Domain域参数上看是使能了idle-cut参数的：

#

domain name ytu

 authorization-attribute idle-cut 120 20480

 authentication portal radius-scheme srun

 authorization portal radius-scheme srun

 accounting portal radius-scheme srun

#

<SR8808-X>dis domain ytu

Domain: ytu

  Current state: Active

  State configuration: Active

………

  Authorization attributes:

    Idle cut: Enabled              //idle-cut参数生效中

      Idle timeout: 120 minutes

      Flow: 20480 bytes

      Traffic direction: Both

        根据现场情况分析，并未发现设备当前有什么问题，此时问题陷入了僵局，后来现场工程师进行了测试：

（1）新地址认证可以下发idle-cut参数

（2）没有下发idle-cut参数的用户踢掉后重新认证可以下发idle-cut参数   

        根据现场测试情况发现，我们设备目前认证过程中idle-cut参数下发正常。后续工程师和现场客户确认，现场的idle-cut参数为后期加入的，前期并没有该参数。 并且，未正常下发idle-cut参数的用均为设备上添加idle-cut参数前，已经进行认证上线的用户。 

       后续和产品线工程师确认：认证属性均由服务器和设备下发，认证之后再下发的idle-cut自然无效，因此，idle-cut参数需认证前配置才能下发给新认证上线的用户。