[lug] I have a problem, but what is it?

[Tkil]

it sounds like the server just croaked.  any error messages on the
console?  anything in /var/log/messages (on the *server*, not on the
linux client).

linux is more stable than most, but it still has the potential to fall 
over.  can  you ping outside hosts directly from the "internet server" 
(i presume you mean "masquerading firewall", but i'm not sure).

the decay of SMB services, no DHCPACK, etc, all sounds like your
server has locked up.  either that, or i'm seriously misunderstanding
your questions.  can you at least ping the server from one of its
erstwhile clients?

this sort of thinking is the bread and butter of debugging network
configurations:  think logically, and think from the bottom up.
first, check the node itself (in this case, the server) to see if it
is running correctly: log files, console errors, pinging across the
WAN, pinging from server into your LAN.  next, test the connection
between internal client and server: first ping, to see if you have any 
IP connectivity at all; then see if you can telnet into server from an 
internal client (if you have rules set to allow you to do so), try to
ping from internal client to outside machine (testing icmp masq on
server), etc, etc.

t.
-- 
Tkil * <URL: http://slinky.scrye.com/~tkil> * hopelessly hopeless romantic.
  "So amplify this little one 	|   She hears as much as she can see
   She's a volume freak       	|   And what she sees, she can't believe."
        -- Catherine Wheel, _Happy Days_, "Judy Staring At The Sun"