The /etc/ppp/ip-up and /etc/ppp/ip-down scripts don't export enviroment
variables from pppd:
DEVICE IFNAME IPLOCAL IPREMOTE PEERNAME SPEED ORIG_UID PPPLOGNAME CONNECT_TIME
BYTES_SENT BYTES_RCVD LINKNAME
Not all of these are available as command-line args, so they must be exported.
Please verify this with a newer version of Red Hat Enterprise Linux or
Fedora Core and reopen it against the new version if it still occurs.
Closing as "not a bug" for now.