ZyXEL UAG715 User Guide - Page 59

VPN Advanced Wizard - Phase 2

Page 59 highlights

Chapter 4 Quick Setup Wizards • Encryption Algorithm: 3DES and AES use encryption. The longer the key, the higher the security (this may affect throughput). Both sender and receiver must use the same secret key, which can be used to encrypt and decrypt the message or to generate and verify a message authentication code. The DES encryption algorithm uses a 56-bit key. Triple DES (3DES) is a variation on DES that uses a 168-bit key. As a result, 3DES is more secure than DES. It also requires more processing power, resulting in increased latency and decreased throughput. AES128 uses a 128-bit key and is faster than 3DES. AES192 uses a 192-bit key, and AES256 uses a 256-bit key. • 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. • 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 ZyWALL sends a message to the remote IPSec device. If it responds, the ZyWALL transmits the data. If it does not respond, the ZyWALL 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. 4.3.9 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 47 VPN Advanced Wizard: Step 4 • Active Protocol: ESP is compatible with NAT, AH is not. • Encapsulation: Tunnel is compatible with NAT, Transport is not. UAG715 User's Guide 59

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Chapter 4 Quick Setup Wizards
UAG715 User’s Guide
59
Encryption Algorithm
:
3DES
and
AES
use encryption. The longer the key, the higher the
security (this may affect throughput). Both sender and receiver must use the same secret key,
which can be used to encrypt and decrypt the message or to generate and verify a message
authentication code. The DES encryption algorithm uses a 56-bit key. Triple DES (
3DES
) is a
variation on DES that uses a 168-bit key. As a result, 3DES is more secure than DES. It also
requires more processing power, resulting in increased latency and decreased throughput.
AES128
uses a 128-bit key and is faster than 3DES. AES192 uses a 192-bit key, and AES256
uses a 256-bit key.
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.
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
ZyWALL sends a message to the remote IPSec device. If it responds, the ZyWALL transmits the
data. If it does not respond, the ZyWALL 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.
4.3.9
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 47
VPN Advanced Wizard: Step 4
Active Protocol
:
ESP
is compatible with NAT,
AH
is not.
Encapsulation
:
Tunnel
is compatible with NAT,
Transport
is not.