S5130S配置server-unreachable keep-online问题

配置了Windows NPS服务器作为用户MAC认证的Radius服务器，测试认证过程和功能正常。

不过用户担心NPS服务器出现问题会影响连接到这个交换机的所有设备，我们就在在接口上配置了mac-authentication re-authenticate server-unreachable keep-online，然后手动关闭NPS服务器测试，但是大约一个小时后，交换机下连的所有设备都下线了，直到我再启动NPS服务器才恢复正常。

这个是有什么问题呢？

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  ===============display current-cOnfiguration===============  

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 version 7.1.070, Release 6343P08

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 sysname xxxxxx

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 clock timezone HKT add 08:00:00

 clock protocol ntp

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 irf mac-address persistent timer

 irf auto-update enable

 undo irf link-delay

 irf member 1 priority 1

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 mac-authentication 

 mac-authentication domain mac-auth 

 mac-authentication user-name-format mac-address without-hyphen uppercase 

 mac-authentication authentication-method chap

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 lldp global enable

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 password-recovery enable

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vlan 1

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vlan 10

 description Siemens

 ip-subnet-vlan 0 ip 10.16.1.0 255.255.255.0

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vlan 20

 description Schneider

 ip-subnet-vlan 0 ip 172.16.252.0 255.255.0.0

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vlan 30

 description Andover

 ip-subnet-vlan 0 ip 192.168.11.0 255.255.255.0

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vlan 40

 description ALC TSSU Chiller

 ip-subnet-vlan 0 ip 192.168.167.0 255.255.255.0

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 stp global enable

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interface Bridge-Aggregation25

 port link-type trunk

 port trunk permit vlan 1 10 20 30 40

 link-aggregation mode dynamic

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interface NULL0

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interface Vlan-interface1

 ip address 192.168.1.17 255.255.255.0

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interface Vlan-interface10

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interface Vlan-interface20

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interface Vlan-interface30

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interface Vlan-interface40

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interface GigabitEthernet1/0/1

 port link-type hybrid

 port hybrid vlan 1 10 20 30 40 untagged

 port hybrid ip-subnet-vlan vlan 10 

 port hybrid ip-subnet-vlan vlan 20 

 port hybrid ip-subnet-vlan vlan 30 

 port hybrid ip-subnet-vlan vlan 40 

 mac-authentication

 mac-authentication re-authenticate server-unreachable keep-online

 undo mac-authentication offline-detect enable

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