What is anti-replay protocol?

The anti-replay protocol provides Internet Protocol (IP) packet-level security by making it impossible for a hacker to intercept message packets and insert changed packets into the data stream between a source computer and a destination computer.

What is anti-replay attack?

Anti-replay is a sub-protocol of IPsec that is part of Internet Engineering Task Force (IETF). The main goal of anti-replay is to avoid hackers injecting or making changes in packets that travel from a source to a destination.

How does IPsec anti-replay work?

IPsec anti-replay protects networks against anti-replay attacks by using a sliding window mechanism called anti-replay window. This feature checks the sequence number of each received IPsec packet against the current IPsec packet sequence number range of the sliding window.

Does sequence number helps avoiding replay attack?

The first way to prevent replay attacks is to attach timestamps or sequence numbers to each sent message. This will allow the receiver to discard any message with a repeated timestamp or sequence number.

What is anti-replay window size?

To enable the anti-replay-window-size option, you first need to configure the option for each VPN object or at the global level. You can configure the anti-replay window size in the range of 64 to 8192 (power of 2). If the anti-replay window size is not configured, the window size is 64 by default.

What is Isakmp in networking?

The Internet Security Association and Key Management Protocol (ISAKMP) defines the procedures for authenticating a communicating peer, creation and management of Security Associations, key generation techniques, and threat mitigation (e.g. denial of service and replay attacks).

Does SSL prevent replay attacks?

The SSL/TLS channel itself is protected against replay attacks using the MAC (Message Authentication Code), computed using the MAC secret and the sequence number. (The MAC mechanism is what ensures the TLS communication integrity).

What is an ESP packet?

Encapsulating Security Payload (ESP) is a member of the Internet Protocol Security (IPsec) set of protocols that encrypt and authenticate the packets of data between computers using a Virtual Private Network (VPN).

What is IP security in network security?

In computing, Internet Protocol Security (IPsec) is a secure network protocol suite that authenticates and encrypts the packets of data to provide secure encrypted communication between two computers over an Internet Protocol network. It is used in virtual private networks (VPNs).

How do I block ISAKMP?

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.