某局点5560X ipv6直连不通

交换机--------服务器

交换机下挂服务器，从该交换机主动ping 服务器地址不通，也学不到ND表项，但从服务器主动  ping 交换机是可以通，触发一下ping了之后交换机有了服务器的ND表项之后再从该交换机ping服务器也能通

经过检查，发现现场配置了ip urpf strict检查， ip urpf strict检查是检查接收报文的端口与以报文SIP查找fib表得到的下一跳出接口是否一致， 不一致报文就会被丢弃。

当收到NA报文时， 以SIP去查找fib表，只会匹配到网段路由，由于出接口是vlan虚接口， 与接收到报文的物理口不一致，故报文被丢弃。

另外使用6326版本测试，配置了ip urpf stric后，可以通，无法复现现场问题

使用6510版本测试，配置了ip urpf stric 后和现场现象一样，不通，配置松散模式可解决

 经过确认：

NA报文是通过ACL上送CPU的，两个版本ACL上送的CPU动作不一样。R6510版本是copy to cpu， 而R6326版本是trap to cpu，存在差异的原因是，某些场景下需要透传NA报文，因此把动作改为了copy to cpu。

Mrvl芯片的ACl处理在前，配置ip urpf strict后，还会经三层引擎进行urpf检查，而urpf检查失败的处理动作是hard drop，  Hard drop的优先级比copy to cpu高，所以R6510版本直接把报文丢弃，未上送CPU。

对于ACL动作是trap to cpu的情况，不会触发三层引擎进行urpf检查，报文直接上送cpu，所以R326版本没有问题。

R6510版本， NA ACL：

========                                                                      

Acl-Type RX IPv6 High, Stage IPCL 2, Global, Installed, Active                

Prio Mjr/Sub 0x30b/0x9, RuleFormat INGRESS_EXT_NOT_IPV6, Vtcame/Idx 4/33,     

Rule Match --------                                                           

         Global range                                                          

         IP protocol: 0x3a, 0xff                                              

         ICMPV6_Type : 0x8800, 0xfe00                                         

         Mac to me: 1                                                          

Actions --------                                                              

         Account mode  packets,  green and non-green                          

         Copy_to_cpu : Yes                                                     

         Change CPU pkt COS 3                                                 

         Red Deny                                                              

         Red_Copy_to_cpu : No                                                 

         Yel Deny                                                             

         Yel_Copy_to_cpu : No                                                  

MatchedName:47, IPV6_ND_DEST                                                  

Accounting: Hi 0, Lo 0                                                         

========

R6326  NA ACL:

========                                                                       

Acl-Type RX IPv6 High, Stage IPCL 2, Global, Installed, Active                  

Prio Mjr/Sub 0x30b/0x8, RuleFormat INGRESS_EXT_NOT_IPV6, Vtcame/Idx 4/41,      

Rule Match --------                                                            

         Global range                                                           

         IP protocol: 0x3a, 0xff                                               

         ICMPV6_Type : 0x8700, 0xff00                                          

         Mac to me: 1                                                          

Actions --------                                                               

         Account mode  packets,  green and non-green                           

         Redirect : Trap to cpu                                                

         Change CPU pkt COS 3                                                  

         Red Deny                                                              

         Red_Copy_to_cpu : No                                                  

         Yel Deny                                                               

         Yel_Copy_to_cpu : No                                                  

MatchedName:46, IPV6_ND_DEST                                                   

         Skip the following PCL lookups                                         

Accounting: Hi 0, Lo 0    

可以使用松散模式解决 ip urpf loose