CCNA Security 640-554


VPN types:
1- Site to Site (enable both sides to communicate with each others)
2- One direction (token)  (allow other side to access our network)

ISAKMP negotiation consists of 2 phases
- phase 1 create the first tunnel
- phase 2 create the second tunnel which protect the data


VPN Components:

- Symmetrical encryption algorithms (use the same key for encrypting and decrypting data)
     Ex: DES, 3DES, AES, IDEA

- Asymmetrical encryption (use a public and a private key. one key encrypts the data, and the other key in the pair is used to decrypt)
    Ex: RSA, Diffie-Hellman.

- Digital Signature (Encryption of hash using private key, and decryption of hash with the sender's public key)
   Ex: RSA signature

- Diffie-Hellman key exchange (uses a public-private key pair asymmetrical algorithm, but creates final shared secrets (keys) that are then used by symmetrical algorithms.
   Ex: used as one of the many services of IPsec

- confidentiality (encryption algorithms provides this by turning clear text into cipher text)
   Ex: DES, 3DES, AES, RSA, IDEA

- Data Integrity (validates data by comparing hash values)
   Ex: MD5, SHA-1

- Authentication (verifies the peer's identity to the other peer)
 

VPN Commands:

# Show vpn crypto isakmp sa  (to see VPN connection status)