redhat 8.0

coolzero · Post by **coolzero** » Mon Jan 27, 2003 7:54 pm

I can't establish a connection between my computer and my cable modem using redhat 8.0

it is a direct connection using dhcp

any ideas?

DocSilly · Post by **DocSilly** » Mon Jan 27, 2003 10:17 pm

Did it work before ? Is your redhat network setup for DHCP ?
http://www.redhat.com/docs/manuals/linu ... onfig.html
That explains network setup during installation and how to launch the Network Administration Tool.

coolzero · Post by **coolzero** » Mon Jan 27, 2003 10:45 pm

yeah when i installed linux it asked me if i wanted to do it dhcp and i said yes and i checked the network configurations after i booted up the first time and everythign was set to recieve and assign ips dhcp style. when i boot up tho it says eth0: cannot find ip

any way to make the pc recognize the ip?

DocSilly · Post by **DocSilly** » Mon Jan 27, 2003 11:43 pm

You could check if the network hardware works ... check if the NIC LEDs are lit/blinking when the computer is running. If not swap the network cable. Otherwise check the modems manual or your ISPs FAQ about troubleshooting DHCP problems.

coolzero · Post by **coolzero** » Tue Jan 28, 2003 4:06 pm

ok i got the basic connection to work heres what im trying to do now

internet----->linux gateway------>windows pc

there is a direct connection established between the internet and the linux (thats how imt alking to u now)

between linux and windows there is a hub....

linux-hub-windows

so i have two nics in the linux

the problem is i cannot get a connection established between linux and windows

i tried ifdown eth1 (eth1 being the connection the the hub and thereforewindows)

then i typed ifup eth1 and the pc said it could not dtermine an ip adress so i checked dhcp and it was set to autmatic everaything so that means there is a problem assigning the nic with an ip..any ideas

DocSilly · Post by **DocSilly** » Tue Jan 28, 2003 4:38 pm

OK, that's the way I see your setup:

Cablemodem (DHCP) ------- (eth0) Linux gateway (eth1) ----- hub ----- Windows pc

So eth0 seems to work from what I understand and it's eth1 giving yer a hard time. I guess you're working with a static IP on the windows pc ? Or was the windows pc earlier directly on the cablemodem and gets his IP via DHCP ?

- static IPs : you have to add a static private IP to eth1 and your windows pc with the correct submask/gateway etc. (like 192.168.100.1/255.255.255.0)

- DHCP : you would have to run the dhcp demon on eth1 (where eth1 would still get a static IP being the gateway) and windows pc would receive IP via DHCP ... OR you could run a dhcp server on your windows pc ... but that wouldn't make any sense since the Linux pc is supposed to be your gateway and thus needs a static IP

Either way, you need a static IP on your eth1 NIC. Next thing after that would be the routing between eth0 and eth1 with NAT/MASQ/firewall and the whole shebang.

coolzero · Post by **coolzero** » Tue Jan 28, 2003 8:43 pm

i found a nice program or actually it was referred to me called guidedog..its supposed to set up ipmasq witha couple of clicls..i just need to get over the training wheels of dhcp to figure out this static ip

ok so static ip...do i get to pick an ip since there is no dhcp assigning an ip to eth1 any longer?

if i get to pick my own ip...what would be a valid ip adress/?

coolzero · Post by **coolzero** » Tue Jan 28, 2003 8:49 pm

sorry to post twice but by the way here is my current route..maybe you know off hand what NEEDS to be changed manually and what should be left alone

also i forgot to mention for some reason when i reinstalled linux the names eth1 and eth0 got switched so although eth1 is working and eth0 is not but the situation is the same as far as direct cable connection working and routing not working

Destination Gateway Genmask Flags Metric Ref Use Iface
24.220.200.0 * 255.255.254.0 U 0 0 0 eth1
127.0.0.0 * 255.0.0.0 U 0 0 0 lo
default host-1-200-220- 0.0.0.0 UG 0 0 0 eth1

DocSilly · Post by **DocSilly** » Wed Jan 29, 2003 5:09 am

The NIC that goes to your inside network (eth0, right?):

IP: 192.168.100.1
subnet: 255.255.255.0
not sure about gateway/dns here, been months that I setup my own DSL gateway (which died with the HDD and will be replaced this week with FreeBSD setup)

Your PC:

IP: 192.168.100.2
subnet: 255.255.255.0
gateway: 192.168.100.1
DNS: the one from your ISP, should be on their FAQ/helppage somewhere

Internet access from windows pc won't work until you setup the ipmasq etc.

That should at least allow you to network both machines. You'll need SAMBA if ya want to share hdd space.

coolzero · Post by **coolzero** » Wed Jan 29, 2003 8:58 am

sweeeeet. it works!

now that ive done ip masq tho ive been referred to getting a firewall cuz apparently ip masq opens your comptuer up to be used as a gateway...know any good linux firewalls?