On Feb 11, Nate Bohlmann wrote
> I'm hoping someone here has seen the following behavior and can offer
> a solution.  I'm running NAT on an i386 box which is connected through
> to my ISP.  I am running Netscape on a Windows95 box and for the most
> part can browse to my heart's content.  However, on certain sites, 
> it connects and tells me it's transferring data but no data ever comes
> down the pipe (according to the lights on the external modem).  One 
> iste that comes readily to mind is www.weather.com.  This is not a 
> [...]

Could'nt this be the now traditional "icmp filetred" problem ?
I checked, and www.weather.com sends datas with the 'DF' (Don't Fragment) flag
set. This is for path mtu discovery, and is the default behavior of Bill
Gates's (modern:) OSes.
Now, as you're behind a ppp link, I assume your MTU (ifconfig will tell you
that) is 576 or even maybe 296. These 'DF' packets will be rejected by your
ISP (greater than the MTU) with an ICMP message "need fragment" back to
www.weather.com, When www.weather.com get this ICMP message, it will decrease
its packet size and retry.
Now, many sites filter ICMP messages on their firewall, because you can remotly
crash some OSes with such messages. This will also break path MTU discovery,
of course, and communications are impossible if there is a link with a small
MTU on the data path.

A solution to your problem would be to use your ISP's proxy. If he doen't have
one, look for another ISP :)

--
Manuel Bouyer, LIP6, Universite Paris VI.           Manuel.Bouyer@lip6.fr
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