3Com Switch 8800 Family IPsec Module Configuration and Command reference Guide

358 CHAPTER 21: GRE CONFIGURATION COMMANDS
packets. If checksum is disabled at the local end but enabled at the opposite end,
the local end will perform do the opposite.
Related command: interface tunnel.
Example
# Set up a tunnel between the SecBlade_VPN1 interface and SecBlade_VPN2
interface and enable checksum on both ends of the tunnel.
[SecBlade_VPN1-Tunnel3] gre checksum
[SecBlade_VPN2-Tunnel2] gre checksum
gre key Syntax
gre key key-number
undo gre key
view
Tunnel interface view
Parameter
key-number: Identification keyword of the two ends of the tunnel, an integer
ranging from 0 to 4294967295.
Description
Use the gre key command to set identification keyword of the tunnel interface,
and by this feeble security mechanism avoid incorrectly identifying or receiving
packets from undesired places.
Use the undo gre key command to delete this configuration.
By default, the system does not assign identification keyword to the tunnel.
Regarding the setting of key-number, you are required either to specify the same
key-number at both ends of the tunnel or to specify it at neither of the two ends.
Related command: interface tunnel.
Example
# Set up a tunnel between SecBlade_VPN1 and SecBlade_VPN2 and set the
identification keyword of the tunnel.
[SecBlade_VPN1-Tunnel3] gre key 123
[SecBlade_VPN2-Tunnel2] gre key 123
interface tunnel Syntax
interface tunnel number
undo interface tunnel number
view
System view