FreeBSD 4.10, dial-up, cvsup, ports

[Feng]

Hi, People,

I had to switch from a ADSL to a dial-up connection and I had to change 
the settings on my FreeBSD 4.10 box.

After reading The Handbook, I had sucessfully connected to the ISP, but 
there are times that the  ppp does not work correctly:
- cvsup'ping hangs during the middle of an update,
- fetch'es during a "make install" ports also hangs

I have configured /etc/ppp/{ppp.config,ppp.linkup}, and set /etc/.conf:
ppp_enable="YES"
ppp_profile="provider"

Does anyone have any idea of what is going on?

Feng

<PS: since I am not on my BSD box, I will not be able to answer promptly>