ZyXEL Communications UAG2100, Руководство пользователя

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Chapter 5 Quick Setup Wizards
UAG Series User’s Guide
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• Key Group : DH5 is more secure than DH1 or DH2 (although it may affect throughput). DH1
(default) refers to Diffie-Hellman Group 1 a 768 bit random number. DH2 refers to Diffie-Hellman
Group 2 a 1024 bit (1Kb) random number. DH5 refers to Diffie-Hellman Group 5 a 1536 bit
random number.
• SA Life Time : Set how often the UAG renegotiates the IKE SA. A short SA life time increases
security, but renegotiation temporarily disconnects the VPN tunnel.
• NAT Traversal : Select this if the VPN tunnel must pass through NAT (there is a NAT router
between the IPSec devices).
Note: The remote IPSec device must also have NAT traversal enabled. See the help in the
main IPSec VPN screens for more information.
• Dead Peer Detection (DPD) has the UAG make sure the remote IPSec device is there before
transmitting data through the IKE SA. If there has been no traffic for at least 15 seconds, the
UAG sends a message to the remote IPSec device. If it responds, the UAG transmits the data. If
it does not respond, the UAG shuts down the IKE SA.
• Authentication Method : Select Pre-Shared Key to use a password or Certificate to use one
of the UAG’s certificates.
5.3.9 VPN Advanced Wizard - Phase 2
Phase 2 in an IKE uses the SA that was established in phase 1 to negotiate SAs for IPSec.
Figure 54
VPN Advanced Wizard: Phase 2 Settings
• Active Protocol : ESP is compatible with NAT, AH is not.
• Encapsulation : Tunnel is compatible with NAT, Transport is not.
• Encryption Algorithm : 3DES and AES use encryption. The longer the AES key, the higher the
security (this may affect throughput). Null uses no encryption.
• Authentication Algorithm : MD5 gives minimal security and SHA512 gives the highest
security. MD5 (Message Digest 5) and SHA (Secure Hash Algorithm) are hash algorithms used to
authenticate packet data. The stronger the algorithm the slower it is.
• SA Life Time : Set how often the UAG renegotiates the IKE SA. A short SA life time increases
security, but renegotiation temporarily disconnects the VPN tunnel.