Westermo MRD-3x0 - Manual (Page 117)

117 6623-3201
General IPsec Configuration
Enabled
Check the box to enable the IPsec VPN. Default is disdisabled.
NAT traversal enabled & keepalive period (secs)
Check box to enable NAT Traversal and set the keepalive
time.
NAT Traversal •
When passing through a Network Address
Translator (NAT) an IP packet is modified in such
a way that is incompatible with Internet Protocol
Security (IPsec). NAT-Traversal protects the
original IPsec encoded packet by encapsulating it
within another layer of UDP and IP headers. If the
wireless interface of the MRD-3xx is allocated
a dynamic and private IP address then the con-
nection to the Internet will be via a Network
Address Translator (NAT), this will require the
use of NAT-Traversal for IPsec to establish a con-
nection.
Keepalive Period •
NAT keepalives are used to keep the dynamic
NAT mapping alive during a connection between
two peers. NAT keepalives are UDP packets
with an unencrypted payload of 1 byte. Although
similar to dead peer detection (DPD), NAT keep-
alives are different, DPD is used to detect peer
status, while NAT keepalives are sent if the IPSec
entity did not send or receive the packet at a
specified period of time.
IPsec MTU
Maximum Transmission Unit (MTU) is the size (in bytes) of
the largest packet which can be sent over the IPsec tunnel.
Leave this value blank to use the default setting.