Users Manual Part 2

Device Configuration
VPN – GRE
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BEC 4700A / 4700AZ User Manual
TUN (IP over GRE)
TUN is in layer 3, networking level which routes packets via GRE tunnels.
Interface: Select a WAN interface to establish a tunnel with the remote VPN device.
Remote Gateway IP: Enter the remote GRE WAN IP address.
Tunnel Local IP Address & Remote IP Address (Virtual Interface): Enter a virtual IP address for
local and peer network of the GRE tunnel.
Tunnel Network Netmask (Virtual Interface): Enter the Netmask for this virtual interface.
NOTE: The virtual Local and Remote IP addresses must in same subnet and cannot be existed or used in both networks.
Remote Network IP Address: Enter the actual remote LAN network IP address.
Remote Network Netmask: Enter the actual remote LAN network Netmask.
Enable Keepalive: Check the box to enable the keepalive. The system will detect remote peer is still
alive or lost. If no responses from the remote peer after certain times, #-of-retry-time x interval, the
connection will get dropped.
Keep-alive Retry Times: Set the keep-alive retry times, default is 3.
Keep-alive Interval: Set the keep-alive Interval, unit in seconds. Default is 5 seconds.
Example: Keepalive retry time (3) x keepalive interval (5) = 15 seconds. If no responses for 15 seconds,
GRE connection will get aborted.
MTU: Maximum Transmission Unit in byte. The size of the largest datagram (excluding media-specific
headers) an IP attempts to send through the interface.
Key: This tunnel key has a maximum string of 5 containing alphanumeric characters. Both sides, local
and remote, should use the same key.