I've set up pppoe-server, which would spawn a pppd process on incoming
connection. And I've also set up pppd to authenticate users through a
radius server.

In the /etc/ppp/options file I added:
plugin radius.so
radius-config-file /etc/radiusclient/radiusclient.conf

I've modified the content of radiusclient.conf appropriately, however
when I initiate pppoe connection from another machine, it got stuck in
the authentication process. I ran tcpdump and didn't see any packets
from the server going out to the radius server.
In /var/log logfile I see "LCP: timeout sending Config-Requests" error
before it terminates the connection.

Then I also found out that pppd doesn't look at the radiusclient.conf
file because when I change the parameter of "radius-config-file" option
into a bogus filename, it didn't return any error.

Can somebody help me with this? Has anyone successfully setup
pppoe-server with radius authentication?

Thanks in advance.