I was planning to use ER605 routers for VPN tunnel connection between branch offices and main office. The configuration would be to use the main fiber optic gigabit link for primary WAN and a 4G USB m

When configuring an openVPN client it only accepts an IP address for the server and not a domain name. If you enter a FQDN in the "Remote server" field, you get the error "Invalid IP address format".