Specifications

2-341
Cisco Catalyst Blade Switch 3120 for HP Command Reference
OL-12248-02
Chapter 2 Cisco Catalyst Blade Switch 3120 for HP Cisco IOS Commands
permit (IPv6 access-list configuration)
Command History
Usage Guidelines The permit (IPv6 access-list configuration mode) command is similar to the permit (IPv4 access-list
configuration mode) command, but it is IPv6-specific.
Use the permit (IPv6) command after the ipv6 access-list command to enter IPv6 access-list
configuration mode and to define the conditions under which a packet passes the access list.
Specifying IPv6 for the protocol argument matches against the IPv6 header of the packet.
By default, the first statement in an access list is number 10, and the subsequent statements increment
by 10.
You can add permit, deny, or remark statements to an existing access list without re-entering the entire
list. To add a new statement anywhere other than at the end of the list, create a new statement with an
appropriate entry number that falls between two existing entry numbers to show where it belongs.
See the ipv6 access-list command for more information on defining IPv6 ACLs.
Note Every IPv6 ACL has implicit permit icmp any any nd-na, permit icmp any any nd-ns, and deny ipv6
any any statements as its last match conditions. The two permit conditions allow ICMPv6 neighbor
discovery. To disallow ICMPv6 neighbor discovery and to deny icmp any any nd-na or icmp any any
nd-ns, there must be an explicit deny entry in the ACL. For the three implicit statements to take effect,
an IPv6 ACL must contain at least one entry.
The IPv6 neighbor discovery process uses the IPv6 network layer service. Therefore, by default, IPv6
ACLs implicitly allow IPv6 neighbor discovery packets to be sent and received on an interface. In IPv4,
the Address Resolution Protocol (ARP), which is equivalent to the IPv6 neighbor discovery process, uses
a separate data link layer protocol. Therefore, by default, IPv4 ACLs implicitly allow ARP packets to be
sent and received on an interface.
Both the source-ipv6-prefix/prefix-length and destination-ipv6-prefix/prefix-length arguments are used
for traffic filtering (the source prefix filters traffic based upon the traffic source; the destination prefix
filters traffic based upon the traffic destination).
The switch supports IPv6 address matching for a full range of prefix-lengths.
The fragments keyword is an option only if the operator [port-number] arguments are not specified.
This is a list of ICMP message names:
Release Modification
12.2(40)EX This command was introduced.
beyond-scope destination-unreachable
echo-reply echo-request
header hop-limit
mld-query mld-reduction
mld-report nd-na
nd-ns next-header
no-admin no-route
packet-too-big parameter-option