ZyXEL Communications ZyWALL 110 Handbook page 121

Go to Authentication section, enter Pre-shared Key and choose negotiation Mode the same as
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the peer ZyWALL/USG's.
Figure 269 VPN > IPsec > Wizard > Custom VPN Tunnel (No Template) > Authentication
Configure Phase 1 Proposal and Diffie-Hellman Group as the peer ZyWALL/USG Advanced Settings'
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Phase 1 Settings > Proposal and Key Group.
Figure 270 VPN > IPsec > Wizard > Custom VPN Tunnel (No Template) > Phase 1 Proposal
Go to Phase 2 Selectors > Advanced and configure Phase 2 Proposal as the peer ZyWALL/USG
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Advanced Settings' Phase 2 Settings > Proposal.
Set Local Address to be the IP address range of the network connected to the FortiGate and
Remote Address to be the IP address range of the network connected to the ZyWALL/USG.
Make sure you uncheck Enable Perfect Forvward Secrecy (PFS) if this function is disabled in the
peer ZyWALL/USG.
Chapter 4 Create Site-to-Site VPN Tunnels
ZyWALL/USG Series User's Guide
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