help PC dhcp Internet ok but local network no Internet

help PC dhcp Internet ok but local network no Internet

Post by Nadi » Thu, 07 Nov 2002 10:48:33



hello i'm a newbie in the beautiful world of linux!

here it goes :

Same PC Red-Hat 8.0 FireWall/Server

eth0 DHCP =
DEVICE=eth0
BOOTPROTO=dhcp
ONBOOT=yes
HWADDR=00:05:5d:f3:f5:2b
USERCTL=no
PEERDNS=no
TYPE=Ethernet

eth1 192.168.0.1 =
DEVICE=eth1
BOOTPROTO=none
IPADDR=192.168.0.1
NETMASK=255.255.255.0
NETWORK=192.168.0.0
ONBOOT=yes
HWADDR=00:05:5d:f3:f6:77
USERCTL=no
PEERDNS=no
TYPE=Ethernet

iptables :
here what i have put on a shell to configure my iptables :

echo 1 > /proc/sys/net/ipv4/ip_forward

iptables -F INPUT
iptables -F OUTPUT
iptables -F FORWARD
iptables -t nat -F POSTROUTING
iptables -t nat -F PREROUTING
iptables -t nat -F OUTPUT
iptables -t mangle -F POSTROUTING
iptables -t mangle -F PREROUTING
iptables -t mangle -F OUTPUT
iptables -t nat -A POSTROUTING -s 192.168.0.0/24 -d 0/0 -j MASQUERADE

when i tested it :

iptables -L

Chain INPUT (policy ACCEPT)
target     prot opt source               destination

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

So it's seems ok for the Firewall iptables

My second PC is a Windows 2000
ip 192.168.0.3
gw 192.168.0.1
my dns are ok too

My third PC is Linux Mandrake
ip 192.168.0.2
gw 192.168.0.1
my dns are ok too

The problem is :

MY PC Firewall/server (eth0 - eth1) surf on the INternet without
problem

My second and third PC of my local network (windows 2000 + Linux) are
not surfing on the net!!! Why?

My cable are ok, all my PCs are pinging each other
i can ping

192.168.0.1
192.168.0.2
192.168.0.3

to all my PC (+ the broadcast)

So to resume : 1 PC is going to Internet and all my network PCs do not
go to Internet! on them i cannot ping IP and i cannot ping URL
(exemple i cannot ping xxx.xxx.xxx.xxx or www.linux.org) but on my PC
dhcp i can ping xxx.xxx.xxx.xxx. and ping www.linux.org!

Help me my world will be a better place! :-)

 
 
 

1. local network no Internet PC firewall go to Internet

hello i'm a newbie in the beautiful world of linux!

here it goes :

Same PC Red-Hat 8.0 FireWall/Server

eth0 DHCP =
DEVICE=eth0
BOOTPROTO=dhcp
ONBOOT=yes
HWADDR=00:05:5d:f3:f5:2b
USERCTL=no
PEERDNS=no
TYPE=Ethernet

eth1 192.168.0.1 =
DEVICE=eth1
BOOTPROTO=none
IPADDR=192.168.0.1
NETMASK=255.255.255.0
NETWORK=192.168.0.0
ONBOOT=yes
HWADDR=00:05:5d:f3:f6:77
USERCTL=no
PEERDNS=no
TYPE=Ethernet

iptables :
here what i have put on a shell to configure my iptables :

echo 1 > /proc/sys/net/ipv4/ip_forward

iptables -F INPUT
iptables -F OUTPUT
iptables -F FORWARD
iptables -t nat -F POSTROUTING
iptables -t nat -F PREROUTING
iptables -t nat -F OUTPUT
iptables -t mangle -F POSTROUTING
iptables -t mangle -F PREROUTING
iptables -t mangle -F OUTPUT
iptables -t nat -A POSTROUTING -s 192.168.0.0/24 -d 0/0 -j MASQUERADE

when i tested it :

iptables -L

Chain INPUT (policy ACCEPT)
target     prot opt source               destination

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

So it's seems ok for the Firewall iptables

My second PC is a Windows 2000
ip 192.168.0.3
gw 192.168.0.1
my dns are ok too

My third PC is Linux Mandrake
ip 192.168.0.2
gw 192.168.0.1
my dns are ok too

The problem is :

MY PC Firewall/server (eth0 - eth1) surf on the INternet without
problem

My second and third PC of my local network (windows 2000 + Linux) are
not surfing on the net!!! Why?

My cable are ok, all my PCs are pinging each other
i can ping

192.168.0.1
192.168.0.2
192.168.0.3

to all my PC (+ the broadcast)

So to resume : 1 PC is going to Internet and all my network PCs do not
go to Internet! on them i cannot ping IP and i cannot ping URL
(exemple i cannot ping xxx.xxx.xxx.xxx or www.linux.org) but on my PC
dhcp i can ping xxx.xxx.xxx.xxx. and ping www.linux.org!

Help me my world will be a better place! :-)

ps : i ahve a cable modem

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