No DNS after modem connect

I'm using the hsfmodem driver with a Dell D600 laptop, & FC3.  It seems 
to install, configure and dial just fine, but after I connect to my ISP, 
no DNS will work.  I think I have the connect configured to 
automatically get all DNS & IP settings from my ISP, & indeed, I can 
ping my ISP and other net resources....just can't get to them in a 
browser with a name (i.e.....www.linuxant.com just won't work).

Any ideas anyone ?

Thanks in advance,
- Gary -