Solution:

Must have an available static IP address or dynamic IP address of theSIM card in case of using translation of dynamically assigned IP addresses to DynDNSdomain name. In this case, Linux server (CISCO router) is initiator and establishes IPsec tunnel. Configuration via web interface If addresses of tunnel ends are visible to one another, all you have to do is specify these items:Description, Remote Subnet and Remote Subnet Mask. If not (one end of the tunnel is in a private network), it is necessary to enable NAT Traversal. If NAT Traversal is active, it is also necessary to set Remote ID. As the ID has to be filled FQDN (Fully Qualified Domain Name Detection of the successful establishment of the tunnel Information about the active IPsec tunnel can be found in the Status section on the IPsec page of the router web interface. Network Status