Draytek Vigor2136 Series User Manual page 214

Available settings are explained as follows:
Item
Enabled
Certificate
Preferred Local ID
General Site-to-Site
PSK
XAuth User PSK
Mode
Accept VPN
Connections on
Description
Switch the toggle to enable/disable the settings.
Authentication Settings for Dynamic Peer
It usually applies to those teleworkers or VPN sites that use dynamic
IP addresses and IPsec-related VPN connections. There are two
methods to authenticate IPsec connections - Certificate (X.509) and
Pre-Shared Key(PSK).
To set up certificates on the router, go to the
Configuration>>Certificates section.
Select Alternative Subject Name or Subject Name.
Specify the preferred local ID information (Alternative Subject Name
First or Subject Name) for IPsec authentication.
Pre-Shared key - Define the PSK key for general authentication.
Pre-Shared Key - Define the PSK key for IPsec XAuth authentication.
More settings –
Maximum TCP segment size (VPN MSS)
Set the maximum segment size (MSS) for different VPN types.
Auto Adjustment by WAN MTU – VPN MSS is the maximum data size
that can be sent in a single TCP packet. It should be set to a value
lower than the network's MTU to prevent fragmentation.
Manually - Please specify the MSS values for each type to avoid
packets cut by MTU during the data transmission period via the IPsec
VPN connection.
IPsec

WireGuard

OpenVPN

Listen on Interface
Select the WAN interfaces to accept IPsec VPN connections.
All Interfaces – Accept the VPN connections on all WAN interfaces.
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