I am confused with my network settings. The problem I am having is that my linux box is setup as a gateway to my cable modem and although everything works alright on the linux box itself, any machines connected as clients don't get dns. That is, they can ping ip's but not names such as yahoo.com.

running ipconfig -all on a client yields:

(I am copying this by hand)
....
Dhcp enabled . .. : yes
autoconfiguration enabled: . . . : yes
IP address. . . .: 192.168.0.99
Subnet mask . .. .. : 255.255.255.0
Default gateway: . . . : 192.168.0.1
DHCP server . . . . : 192.168.0.1
DNS servers . . .. : 216.69.192.11
216.69.192.12
....

ifconfig -a on gateway:
eth0 Link encap:Ethernet HWaddr 00:50:8D:4B:6D:C8
inet addr:69.133.77.53 Bcast:255.255.255.255 Mask:255.255.254.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:116075 errors:0 dropped:0 overruns:0 frame:0
TX packets:5167 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:9318394 (8.8 MiB) TX bytes:593489 (579.5 KiB)
Interrupt:19 Base address:0x2000

eth1 Link encap:Ethernet HWaddr 00:48:54:8A:79:04
inet addr:192.168.0.1 Bcast:192.168.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:136603 errors:0 dropped:0 overruns:0 frame:0
TX packets:116592 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:149855159 (142.9 MiB) TX bytes:12510047 (11.9 MiB)
Interrupt:22 Base address:0x4000

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:6511 errors:0 dropped:0 overruns:0 frame:0
TX packets:6511 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:546272 (533.4 KiB) TX bytes:546272 (533.4 KiB)

--------------------------------
iptables (yes I know they are basic, I want to get it working first):

#!/bin/bash
#

# First clear out all the rules and close everything off but let outbound packets through
iptables -P INPUT ACCEPT
iptables -F INPUT
iptables -P OUTPUT ACCEPT
iptables -F OUTPUT
iptables -P FORWARD ACCEPT
iptables -F FORWARD
iptables -F -t nat

# turn on forwarding in the kernel
echo 1 > /proc/sys/net/ipv4/ip_forward

# Open up the internal network
iptables -A INPUT -i lo -s 127.0.0.0/8 -j ACCEPT
iptables -A INPUT -i eth1 -j ACCEPT

# Allow SSH from outside
iptables -A INPUT -i eth0 -p tcp --dport 22 -j ACCEPT
iptables -A INPUT -i eth0 -m state --state ESTABLISHED,RELATED -j ACCEPT

# IP Masquerading
#iptables -A FORWARD -i eth0 -o eth1 -m state --state ESTABLISHED,RELATED -j ACCEPT
#iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT
#iptables -A FORWARD -i eth1 -j ACCEPT
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
iptables -t nat -A POSTROUTING -s 192.168.0.0/24 -o eth0 -j SNAT --to-source 69.133.77.53

# Port Forwarding
#iptables -A FORWARD -p tcp -i eth0 -j ACCEPT

-------------------------------
route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.0.0 * 255.255.255.0 U 0 0 0 eth1
69.133.76.0 * 255.255.254.0 U 0 0 0 eth0
default cpe-069-133-076 0.0.0.0 UG 0 0 0 eth0
default 192.168.0.1 0.0.0.0 UG 0 0 0 eth1

-------------------------------
dhcpd.conf
subnet 192.168.0.0 netmask 255.255.255.0 {
range 192.168.0.50 192.168.0.150;
option domain-name-servers 216.69.192.11, 216.69.192.12;
option domain-name "bobdole.gov";
option routers 192.168.0.1;
option broadcast-address 192.168.0.255;
default-lease-time 600;
max-lease-time 7200;
}


So can anyone help me?

You have 2 default routes listed, your external ip and an internal ip...
Delete the internal one;
route del default gw 192.168.0.1

And you only need one Masq/Snat rule, chose 1 and delete the other...

inet addr:69.133.77.53 Bcast:255.255.255.255 Mask:255.255.254.0
Check the netmask setting here.. it's awfully wide...
The broadcast isn't correct either..

From the workstations, in a command prompt, do
nslookup www.something.com
and see if it resolves...

If not, from win machines do
nslookup www.something.com 216.69.192.11 &
nslookup www.something.com 216.69.192.12
to test both servers.
From here I get REJECTs, prob restricted to your ip range.

There's nothing "wrong" with the rule list, but do
iptables-save
to print it on the screen and check what is actually running..

If it's still no-go,
add some logging rules to follow the packets through the tables..
eg iptables -t nat -I PREROUTING -i eth1 -p udp --dport 53 -j LOG --log-prefix "1 "
iptables -t nat -I POSTROUTING -o eth0 -p udp --dport 53 -j LOG --log-prefix "2 "
iptables -t nat -I PREROUTING -i eth0 -p udp --sport 53 -j LOG --log-prefix "3 "
iptables -t nat -I POSTROUTING -o eth1 -p udp --sport 53 -j LOG --log-prefix "4 "

Thanks, it's working now.