ZyXEL Communications VPN Series Handbook page 3

What Could Go Wrong? ...................................................................... 84
How to Configure IPSec Site to Site VPN while one Site is behind a NAT
router ............................................................................................................ 86
Set Up the ZyWALL/USG IPSec VPN Tunnel of Corporate Network
(HQ) ....................................................................................................... 86
Set Up the ZyWALL/USG IPSec VPN Tunnel of Corporate Network
(Branch) ................................................................................................. 90
Set Up the NAT Router (Using ZyWALL USG device in this example) 94
Test the IPSec VPN Tunnel .................................................................... 96
What Could Go Wrong? ...................................................................... 97
How to Configure Hub-and-Spoke IPSec VPN ......................................... 98
Set Up the IPSec VPN Tunnel on the ZyWALL/USG by Using VPN
Concentrator Hub_HQ-to-Branch_A .................................................. 99
Hub_HQ-to-Branch_B ......................................................................... 103
Hub_HQ Concentrator ....................................................................... 107
Spoke_Branch_A ................................................................................ 108
Spoke_Branch_B ................................................................................. 113
Test the IPSec VPN Tunnel .................................................................. 118
What Could Go Wrong? .................................................................... 122
Set Up the IPSec VPN Tunnel of ZyWALL/USG without Using VPN
Concentrator Hub_HQ-to-Branch_A ................................................ 124
Hub_HQ-to-Branch_B ......................................................................... 127
Spoke_Branch_A ................................................................................ 130
Spoke_Branch_B ................................................................................. 133
Test the IPSec VPN Tunnel .................................................................. 136
What Could Go Wrong? .................................................................... 139
How to Use Dual-WAN to Perform Fail-Over on VPN Using the VPN
Concentrator ............................................................................................. 141
Set Up the IPSec VPN Tunnel on the ZyWALL/USG Hub_HQ-to-
Branch_A ............................................................................................. 142
Hub_HQ-to-Branch_B ......................................................................... 145
Hub_HQ Concentrator ....................................................................... 148
Spoke_Branch_A ................................................................................ 149
Spoke_Branch_B ................................................................................. 152
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