I get this error after pushing Framed-IP-Address from my radius server to OpenVPN. Thats because I don't know how to also push the remote ip (which in my case is the framed ip plus 1)
Since you are using --dev tun with a point-to-point topology, the second argument to --ifconfig must be an IP address. You are using something (255.255.255.0) that looks more like a netmask. (silence this warning with --ifconfig-nowarn)
What would you suggest me to do in this situation to make OpenVPN and Freeradius get along on this matter?
P.S. I know I can use client-config-dir but I really want to use radius for this one.