Technical Tip: 'duplicate remote gateway' error

When a second IPsec VPN tunnel is created with the same remote gateway IP, it shows an error at the end with 'duplicate remote gateway'.

'The remote gateway is a duplicate of another IPsec gateway entry (The existing phase1 name)
object check operator error, -34, discard the setting
Command fail. Return code -34'.

Use the same external IP with a different port to use the same external server, or it is necessary to change the external IP, as the same information will conflict. 

As a limitation, it is not possible to use the same remote gateway IP in the IPsec tunnel because it will conflict with policy, static route, and phase-2 selectors.

It is then not possible to choose the same remote gateway IP on another tunnel. 

However, in ADVPN, it is possible to choose the same remote gateway IP by differentiating traffic by network-id. Below are the settings that need to be set:

config vpn ipsec phase1-interface  

    edit <tunnel name>  

        set network-overlay enable  

        set network-id x <----- Any integer number .

Related document:

Enabling ADVPN and adding overlay IDs