ZyWALL 5/35/70 Series User’s Guide
If the remote secure gateway has a static WAN IP address, enter it in the Remote Gateway Address field. You may alternatively enter the remote secure gateway’s domain name (if it has one).
You can also enter a remote secure gateway’s domain name in the Remote Gateway Address field if the remote secure gateway has a dynamic WAN IP address and is using DDNS. The ZyWALL has to rebuild the VPN tunnel each time the remote secure gateway’s WAN IP address changes (there may be a delay until the DDNS servers are updated with the remote gateway’s new WAN IP address).
19.4.1 Dynamic Remote Gateway Address
If the remote secure gateway has a dynamic WAN IP address and does not use DDNS, enter
0.0.0.0as the remote gateway’s address. In this case only the remote secure gateway can initiate SAs. This may be useful for telecommuters initiating a VPN tunnel to the company network. See Section 19.18 on page 333 for configuration examples.
Note: The Remote Gateway Address may be configured as 0.0.0.0 only when using IKE key management and not Manual key management.
19.5 Nailed Up
When you initiate an IPSec tunnel with nailed up enabled, the ZyWALL automatically renegotiates the tunnel when the IPSec SA lifetime period expires (see Section 19.8 on page 309 for more on the IPSec SA lifetime). In effect, the IPSec tunnel becomes an always on connection after you initiate it. Both IPSec routers must have a
If the ZyWALL has its maximum number of simultaneous IPSec tunnels connected to it and they all have nailed up enabled, then no other tunnels can take a turn connecting to the ZyWALL because the ZyWALL never drops the tunnels that are already connected.
Note: When there is outbound traffic with no inbound traffic, the ZyWALL automatically drops the tunnel after two minutes.
19.6 NAT Traversal
NAT traversal allows you to set up a VPN connection when there are NAT routers between the two IPSec routers.
Chapter 19 VPN Screens | 306 |