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Cisco Nexus 5500 Series NX-OS Security Command Reference
OL-27883-02
Chapter       D Commands
deny ipv6 (IPv6)
Command History
Usage Guidelines A newly created IPv6 ACL contains no rules.
When the device applies an IPv6 ACL to a packet, it evaluates the packet with every rule in the ACL. 
The device enforces the first rule whose conditions are satisfied by the packet. When the conditions of 
more than one rule are satisfied, the device enforces the rule with the lowest sequence number.
Source and Destination
You can specify the source and destination arguments in one of several ways. In each rule, the method 
you use to specify one of these arguments does not affect how you specify the other. When you configure 
a rule, use the following methods to specify the source and destination arguments:
• Address and variable-length subnet mask—You can use an IPv6 address followed by a 
variable-length subnet mask (VLSM) to specify a host or a network as a source or destination. The 
syntax is as follows:
IPv6-address/prefix-len
This example shows how to specify the source argument with the IPv6 address and VLSM for the 
2001:0db8:85a3:: network:
switch(config-acl)# deny ipv6 2001:0db8:85a3::/48 any
• Host address—You can use the host keyword and an IPv6 address to specify a host as a source or 
destination. The syntax is as follows:
host IPv6-address
This syntax is equivalent to IPv6-address/128.
This example shows how to specify the source argument with the host keyword and the 
2001:0db8:85a3:08d3:1319:8a2e:0370:7344 IPv6 address:
switch(config-acl)# deny ipv6 host 2001:0db8:85a3:08d3:1319:8a2e:0370:7344 any
• Any address—You can use the any keyword to specify that a source or destination is any IPv6 
address. For examples of the use of the any keyword, see the examples in this section. Each example 
shows how to specify a source or destination by using the any keyword.
Examples This example shows how to configure an IPv6 ACL named acl-lab13-ipv6 with rules denying all IPv6 
traffic from the 2001:0db8:85a3:: and 2001:0db8:69f2:: networks to the 2001:0db8:be03:2112:: 
network:
switch# configure terminal 
switch(config)# ipv6 access-list acl-lab13-ipv6 
switch(config-ipv6-acl)# deny ipv6 2001:0db8:85a3::/48 2001:0db8:be03:2112::/64
switch(config-ipv6-acl)# deny ipv6 2001:0db8:69f2::/48 2001:0db8:be03:2112::/64
Release Modification
5.2(1)N1(1) This command was introduced.