ZyXEL Communications SBG5500-A, User Manual

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Chapter 10 VPN
SBG5500 Series User’s Guide
174
10.5.3 The Default_L2TP_VPN_GW IPsec VPN Rule
A default IPsec VPN rule ( Default_L2TP_VPN_GW ) is predefined. It can be edited but cannot be
removed. This rule is used for L2TP VPN exclusively and is disabled by default.
The following table lists the default settings for the Default_L2TP_VPN_GW IPsec VPN.
Encryption This field is applicable when the Active Protocol is ESP. Select which key size and
encryption algorithm to use in the IPsec SA. Choices are:
None - no encryption key or algorithm
3DES - a 168-bit key with the DES encryption algorithm
AES128 - a 128-bit key with the AES encryption algorithm
AES192 - a 192-bit key with the AES encryption algorithm
AES256 - a 256-bit key with the AES encryption algorithm
The SBG and the remote IPsec router must both have at least one proposal that uses
use the same encryption and the same key.
Longer keys are more secure, but require more processing power, resulting in
increased latency and decreased throughput.
Authentication Select which hash algorithm to use to authenticate packet data in the IPsec SA.
Choices are
SHA1 , SHA256 , and SHA512 . SHA is generally considered stronger than
MD5, but it is also slower.
The SBG and the remote IPsec router must both have a proposal that uses the same
authentication algorithm.
Perfect Forward Secrecy
(PFS) Select whether or not you want to enable Perfect Forward Secrecy (PFS) and, if you
do, which Diffie-Hellman key group to use for encryption. Choices are:
DH2 - enable PFS and use a 1024-bit random number
DH5 - enable PFS and use a 1536-bit random number
DH14 - enable PFS and use a 2048-bit random number
PFS changes the root key that is used to generate encryption keys for each IPsec SA.
The longer the key, the more secure the encryption, but also the longer it takes to
encrypt and decrypt information. Both routers must use the same DH key group.
OK Click OK to save your changes.
Cancel Click Cancel to restore your previously saved settings.
Table 71 VPN Connection: Add/Edit
LABEL DESCRIPTION
Table 72 Default settings for Default_L2TP_VPN_GW
GENERAL AUTHENTICATION
Enabled No Pre-Shared Key none
Nailed-up No Certificate none
NAT Traversal Yes Local ID Type IP
Application Scenario Remote Access Content 0.0.0.0
My Address Any Remote ID Type Any
PHASE 1 PHASE 2
Life time 86400 Life time 3600