The script is passed the common name and  IP  address  of
the just-authenticated  client as environmental variables
(see environmental variable sec- tion below).  The script is
also passed the pathname of a not-yet-created temporary file
as $1  (i.e.  the  first  command line argument), to be used
by the script to pass dynamically generated config file
directives back to OpenVPN.

# first local address assigned to the vpn tunnel, then remote
# [ this is not SIPx/CIPx - it's just private addressing for the tunnel ]
ifconfig 10.255.255.10 10.255.255.9
# here you install a new route on the server whenever vpn is established
# you want to put CIP1/32 routed via vpn ip assigned to the remote end of vpn
route 10.13.0.0 255.255.0.0 10.255.255.9
port somePort
[..]

# put your SIP1 here and some port on which server is configured
remote 213.xxx.xxx.xxx somePort
# again - first is local, second - remote address of vpn tunnel
ifconfig 10.255.255.9 10.255.255.10
# you want to put below SIP1/32 routed via vpn ip from far end of the tunnel
route 10.15.0.0 255.255.0.0 10.255.255.10