ZyXEL Communications UAG5100 User Manual page 295

Table 132 Configuration > VPN > IPSec VPN > VPN Connection > Add/Edit (continued)
LABEL DESCRIPTION
Perfect Forward Select whether or not you want to enable Perfect Forward Secrecy (PFS) and, if you
Secrecy (PFS)
do, which Diffie-Hellman key group to use for encryption. Choices are:
none - disable PFS
DH1 - enable PFS and use a 768-bit random number
DH2 - enable PFS and use a 1024-bit random number
DH5 - enable PFS and use a 1536-bit random number
PFS changes the root key that is used to generate encryption keys for each IPSec SA.
The longer the key, the more secure the encryption, but also the longer it takes to
encrypt and decrypt information. Both routers must use the same DH key group.
Related Settings
Zone Select the security zone into which to add this VPN connection policy. Any security
rules or settings configured for the selected zone apply to this VPN connection policy.
Connectivity Check The UAG can regularly check the VPN connection to the gateway you specified to
make sure it is still available.
Enable Select this to turn on the VPN connection check.
Connectivity Check
Check Method Select how the UAG checks the connection. The peer must be configured to respond
to the method you select.
Select icmp to have the UAG regularly ping the address you specify to make sure
traffic can still go through the connection. You may need to configure the peer to
respond to pings.
Select tcp to have the UAG regularly perform a TCP handshake with the address you
specify to make sure traffic can still go through the connection. You may need to
configure the peer to accept the TCP connection.
Check Port This field displays when you set the Check Method to tcp. Specify the port number
to use for a TCP connectivity check.
Check Period Enter the number of seconds between connection check attempts.
Check Timeout Enter the number of seconds to wait for a response before the attempt is a failure.
Check Fail Enter the number of consecutive failures allowed before the UAG disconnects the VPN
Tolerance
tunnel. The UAG resumes using the first peer gateway address when the VPN
connection passes the connectivity check.
Check this Address Select this to specify a domain name or IP address for the connectivity check. Enter
that domain name or IP address in the field next to it.
Check the First Select this to have the UAG check the connection to the first and last IP addresses in
and Last IP
the connection's remote policy. Make sure one of these is the peer gateway's LAN IP
Address in the
address.
Remote Policy
Log Select this to have the UAG generate a log every time it checks this VPN connection.
Inbound/Outbound
traffic NAT
Outbound Traffic
Source NAT This translation hides the source address of computers in the local network. It may
also be necessary if you want the UAG to route packets from computers outside the
local network through the IPSec SA.
Source Select the address object that represents the original source address (or select
Create new Object to configure a new one). This is the address object for the
computer or network outside the local network. The size of the original source
address range (Source) must be equal to the size of the translated source address
range (SNAT).
Chapter 30 IPSec VPN
UAG5100 User's Guide
295