netfilter/iptables/NAT/DNS problems

["PAUL WILLIAMSON" <pwilliamson@mandtbank.com>]

Help!!  I have no hair left!  

I have been over the HOWTO, most exampes I can find 
and I still can't get things working entirely correct. 

I've looked in the archives, and that's gotten me 
about 95% of the way.  But that last 5% is killing 
me.

external net-----firewall/dns-----internal net

I'd like anything sourced from inside to be able to get outside.  
I'd like nothing outside to be able to get in, other 
that traffic that originated from inside.
I'd like ssh to be accepted from only internal 
connections.
I want all my internal network machines to use the 
DNS on the firewall.  The DNS on the firewall is 
pointing to a "real" internet DNS server.
I want all my machines to be NAT'ed going through the 
firewall out to the internet.

I have a cable modem with a dynamically assigned IP 
address, and depending on what range I get assigned 
to, I may end up with different DNS servers.  I'd 
like my internal machines to use the firewall as the 
DNS server, and have the firewall actually do the 
requesting out to the internet.
I can surf the internet from the linux 
firewall/dns box.

I can get as far as being able to ping real ip 
addresses on the internet from any internal machine, 
but I can't ping DNS names of those same sites.  
Obviously, I don't quite have things set up 
correctly.

Also, I can't get ssh to be accepted, PuTTy gives me 
an error that "Software caused connection abort."  

BTW, most internal machines are Windoze2000 or XP.
There are one or two crazy people that run linux 
on their desktop (me included...)  But I'm not too 
concerned, because I think the problem is in how the 
iptable rules are accepting requests on port 53, 
right? 

Please help!

Thanks,
Paul