> Crypto Map Dynamic Configuration Mode Commands
> The Crypto Map Dynamic Configuration Mode is used to configure IPSec tunnels that are created as needed to facilitate subscriber sessions using Mobile IP or L2TP.
> Modification(s) to an existing dynamic crypto map configuration will not take effect until the related security association has been cleared. Refer to the description of the clear crypto security-association command in the Exec Mode Commands chapter for more information.
> end
> Exits the current configuration mode and returns to the Exec mode.
> Product
> All
> Privilege
> Security Administrator, Administrator
> Syntax
> end
> Usage
> Use this command to return to the Exec mode.
> exit
> Exits the current mode and returns to the parent configuration mode.
> Product
> All
> Privilege
> Security Administrator, Administrator
> Syntax
> exit
> Usage
> Use this command to return to the parent configuration mode.
> set
> Configures parameters for the dynamic crypto map.
> Product
> PDSN, HA, GGSN, PDIF
> Privilege
> Security Administrator, Administrator
> Syntax
> set { control-dont-fragment { clear-bit | copy-bit | set-bit } | isakmp natt [keepalive time ] | pfs { group1 | group2 | group5} | phase1-idtype { id-key-id | ipv4-address } [ mode { aggressive | main } ] | phase2-idtype { ipv4-address | ipv4-address-subnet} | security-association lifetime { keepalive | kilo-bytes kbytes | seconds secs } | transform-set transform_name [ transform-set transform_name2 ... transform-set transform_name6 ] }
> no set { pfs | security-association lifetime {keepalive | kilo-bytes | seconds } | phase1-idtype | phase2-idtype | transform-set transform_name [ transform-set transform_name2 ... transform-set transform_name6 ] }
> no
> Deletes the specified parameter or resets the specified parameter to the default value.
> control-dont-fragment { clear-bit | copy-bit | set-bit }
> Controls the don’t fragment (DF) bit in the outer IP header of the IPSec tunnel data packet. Options are:

> • | clear-bit: Clears the DF bit from the outer IP header (sets it to 0).

> • | copy-bit: Copies the DF bit from the inner IP header to the outer IP header. This is the default action.

> • | set-bit: Sets the DF bit in the outer IP header (sets it to 1).

> isakmp natt [keepalive time ]
> Enable IPSec NAT Traversal.
> keepalive time: The time to keep the NAT connection alive in seconds. time must be an integer of from 1 through 3600.
> pfs { group1 | group2 | group5 }
> Specifies the modp Oakley group (also known as the Diffie-Hellman [D-H] group) that is used to determine the length of the base prime numbers that are used for Perfect Forward Secrecy (PFS).

> • | group1: Diffie-Hellman Group1 (768-bit modp)

> • | group2:- Diffie-Hellman Group2 (1024-bit modp)

> • | group5:- Diffie-Hellman Group5 (1536-bit modp)

> phase1-idtype { id-key-id | ipv4-address } [ mode { aggressive | main } ]
> Sets the IKE negotiations Phase 1 payload identifier.
> Default: ipv4-address
> id-key-id: Use ID_KEY_ID as the Phase 1 payload identifier.
> ipv4-address: Use IPV4_ADDR as the Phase 1 payload identifier.
> mode { aggressive | main }: Specify the IKE mode.
> phase2-idtype { ipv4-address | ipv4-address-subnet }
> Sets the IKE negotiations Phase 2 payload identifier.
> Default: ipv4-address-subnet
> ipv4-address: Use IPV4_ADDR as the Phase 2 payload identifier.
> ipv4-address-subnet: Use IPV4_ADDR_SUBNET as the Phase 2 payload identifier.
> security-association lifetime { keepalive | kilo-bytes kbytes | seconds secs }
> Defaults:

> • | keepalive: Disabled

> • | kilo-bytes: 4608000 kbytes

> • | seconds: 28800 seconds

> This keyword specifies the parameters that determine the length of time an IKE Security Association (SA) is active when no data is passing through a tunnel. When the lifetime expires, the tunnel is torn down. Whichever parameter is reached first expires the SA lifetime.

> • | keepalive: The SA lifetime expires only when a keepalive message is not responded to by the far end.

> • | kilo-bytes: This specifies the amount of data in kilobytes to allow through the tunnel before the SA lifetime expires; entered as an integer from 2560 through 4294967294.

> • | seconds: The number of seconds to wait before the SA lifetime expires; entered as an integer from 1200 through 86400.

> Important: If the dynamic crypto map is being used in conjunction with Mobile IP and the Mobile IP renewal timer is less than the crypto map’s SA lifetime (either in terms of kilobytes or seconds), then the keepalive parameter must be configured.
> transform-set transform_name [ transform-set transform_name2 ... transform-set transform_name6 ]
> Specifies the name of a transform set configured in the same context that will be associated with the crypto map. Refer to the command crypto ipsec transform-set for information on creating transform sets.
> You can repeat this keyword up to 6 times on the command line to specify multiple transform sets.
> trasnform_name is the name of the transform set entered as an alphanumeric string from 1 through 127 characters that is case sensitive.
> Usage
> Use this command to set parameters for a dynamic crypto map.
> Example
> The following command sets the PFS group to Group1:
> set pfs group1
> The following command sets the SA lifetime to 50000 KB:
> set security-association lifetime kilo-bytes 50000
> The following command sets the SA lifetime to 10000 seconds:
> set security-association lifetime seconds 10000
> The following command enables the SA to re-key when the tunnel lifetime expires:
> set security-association lifetime keepalive
> The following command defines transform sets tset1 and tset2:
> set transform-set tset1 transform-set tset2

Cisco Systems Inc.
Tel: 408-526-4000
Fax: 408-527-0883