To configure the site-to-site VPN between the two branch offices according to the provided requirements, here are the detailed steps and settings that need to be applied to the VPN concentrators:
Requirements:
Most secure algorithms should be selected.
All traffic should be encrypted over the VPN.
A secret password will be used to authenticate the two VPN concentrators.
VPN Concentrator 1 Configuration:
Phase 1:
Peer IP address: 5.5.5.10 (The IP address of VPN Concentrator 2)
Auth method: PSK (Pre-Shared Key)
Negotiation mode: MAIN
Encryption algorithm: AES256
Hash algorithm: SHA256
DH key group: 14
Phase 2:
Mode: Tunnel
Protocol: ESP (Encapsulating Security Payload)
Encryption algorithm: AES256
Hash algorithm: SHA256
Local network/mask: 192.168.1.0/24
Remote network/mask: 192.168.2.0/24
VPN Concentrator 2 Configuration:
Phase 1:
Peer IP address: 5.5.5.5 (The IP address of VPN Concentrator 1)
Auth method: PSK (Pre-Shared Key)
Negotiation mode: MAIN
Encryption algorithm: AES256
Hash algorithm: SHA256
DH key group: 14
Phase 2:
Mode: Tunnel
Protocol: ESP (Encapsulating Security Payload)
Encryption algorithm: AES256
Hash algorithm: SHA256
Local network/mask: 192.168.2.0/24
Remote network/mask: 192.168.1.0/24
Summary:
Peer IP Address: Set to the IP address of the remote VPN concentrator.
Auth Method: PSK for using a pre-shared key.
Negotiation Mode: MAIN for the initial setup.
Encryption Algorithm: AES256, which is a strong and secure algorithm.
Hash Algorithm: SHA256, which provides strong hashing.
DH Key Group: 14 for strong Diffie-Hellman key exchange.
Phase 2 Protocol: ESP for encryption and integrity.
Local and Remote Networks: Properly configure the local and remote network addresses to match each branch office subnet.
By configuring these settings on both VPN concentrators, the site-to-site VPN will meet the requirements for strong security algorithms, encryption of all traffic, and authentication using a pre-shared key.