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Common questions

What is ISAKMP policy?

What is ISAKMP policy?

The crypto isakmp policy command creates a unique ISAKMP/IKE management connection policy on the router, where each policy requires a separate number. Numbers can range between 110,000. Executing this command takes you to a subcommand mode where you enter the configuration for the policy.

What is the ISAKMP port?

Key Management Protocol (ISAKMP) Description: Port 500 is used by the Internet key exchange (IKE) that occurs during the establishment of secure VPN tunnels. Users of VPN servers and clients may encounter this port.

What is the purpose of ISAKMP in IPSec?

ISAKMP, also called IKE (Internet Key Exchange), is the negotiation protocol that allows hosts to agree on how to build an IPSec security association.


For IKEv2, the SA that carries IKE messages is referred to as the IKE SA, and the SAs for ESP and AH are child SAs. For IKEv1, the corresponding terms for the two types of SAs are “ISAKMP SA” and “IPSec SA”.

Is ISAKMP used in IKEv2?

Is IKEv2 ISAKMP? Main mode uses six ISAKMP messages to establish the IKE SA, but aggressive mode uses only three. IKEv2 uses two exchanges (a total of 4 messages) to create an IKE SA and a pair of IPSec SAs. To create multiple pairs of IPSec SAs, only one additional exchange is needed for each additional pair of SAs.

What is the difference between main mode and aggressive mode in VPN?

Main Mode uses a six-way handshake where parameters are exchanged in multiple rounds with encrypted authentication information. Aggressive Mode uses a three-way handshake where the VPN sends the hashed PSK to the client in a single unencrypted message.

What is crypto ISAKMP aggressive mode?

To block all Internet Security Association and Key Management Protocol (ISAKMP) aggressive mode requests to and from a device, use the crypto isakmp aggressive-mode disable command in global configuration mode. To disable the blocking, use the no form of this command.

Which phase is ISAKMP?

IKE phase 2
IKE phase 2 In this phase, an ISAKMP (Internet Security Association and Key Management Protocol) session is established. This is also called the ISAKMP tunnel or IKE phase 1 tunnel. The IKE phase 1 tunnel is only used for management traffic.

What is ISAKMP group?

The first is the ISAKMP client group. This is created using the command. This command defines the majority of the client configuration and the group policy information that is used to support the IPsec client connections.

What is the difference between IKE and ISAKMP?

IKE establishs the shared security policy and authenticated keys. ISAKMP is the protocol that specifies the mechanics of the key exchange. The confusion, (for me,) is that in the Cisco IOS ISAKMP/IKE are used to refer to the same thing.

What are the 3 protocols used in IPsec?

The last three topics cover the three main IPsec protocols: IPsec Authentication Header (AH), IPsec Encapsulating Security Payload (ESP), and the IPsec Internet Key Exchange (IKE). for both IPv4 and IPv6 networks, and operation in both versions is similar.

What is a ISAKMP packet?

ISAKMP defines payloads for exchanging key generation and authentication data. These formats provide a consistent framework for transferring key and authentication data which is independent of the key generation technique, encryption algorithm and authentication mechanism.