eth0 fixed IP. eth1 DHCP gateway. Need access to eth0

wolfperkins · 08-26-2009, 06:37 AM

The christravel reference must come from your local host file

Code:

grep 192.168.1.6 /etc/hosts

fopetesl · 08-26-2009, 07:28 AM

Quote:

Originally Posted by wolfperkins

The christravel reference must come from your local host file

Code:

grep 192.168.1.6 /etc/hosts

Code:

# cat /etc/hosts
127.0.0.1 localhost.localdomain localhost machine

# The following lines are desirable for IPv6 capable hosts
192.168.1.1 2WIRE133

jschiwal · 08-26-2009, 07:50 AM

Check /etc/networks as well.
You have two host routes for the device. Only have one for the NIC device that connects to the device.

This command should not have been run:
route add -host 192.168.1.6 dev eth1

fopetesl · 08-26-2009, 09:07 AM

Quote:

Originally Posted by jschiwal

Check /etc/networks as well.

Code:

 cat /etc/networks
cat: /etc/networks: No such file or directory

Quote:

This command should not have been run:
route add -host 192.168.1.6 dev eth1

Code:

root@machine:/home/Peter# route add -host 192.168.1.6 dev eth0
root@machine:/home/Peter# route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use 
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
christravel     *               255.255.255.255 UH    0      0        0 eth0
192.168.1.0     *               255.255.255.0   U     0      0        0 eth1
192.16.1.0      *               255.255.255.0   U     0      0        0 eth0
default         2WIRE133        0.0.0.0         UG    0      0        0 eth1
root@machine:/home/Peter# ping 192.168.1.6
PING 192.168.1.6 (192.168.1.6) 56(84) bytes of data.
From 192.168.1.38 icmp_seq=2 Destination Host Unreachable
From 192.168.1.38 icmp_seq=3 Destination Host Unreachable
From 192.168.1.38 icmp_seq=4 Destination Host Unreachable
From 192.168.1.38 icmp_seq=6 Destination Host Unreachable
From 192.168.1.38 icmp_seq=7 Destination Host Unreachable
From 192.168.1.38 icmp_seq=8 Destination Host Unreachable

--- 192.168.1.6 ping statistics ---
9 packets transmitted, 0 received, +6 errors, 100% packet loss, time 7998ms
, pipe 3
root@machine:/home/Peter#

Quote:

You have two host routes for the device. Only have one for the NIC device that connects to the device.

If I knew how or where to modify the "routes" file I would. I have no idea why there are two routes for eth1

zhjim · 08-26-2009, 09:29 AM

You are totaly right I mixed eth1 with eth0.

I guess we should give this a new start. Restart the machine and see what routes are available. Then just add an extra route for that 192.168.1.6.

What I'm not sure of is which route takes precedence. I might just be that the extra route for the 192.168.1.6 host comes after the route entry for the network 192.168.1.0/24.
I'll see if I can dig some up on this

Just a sitenote to be not confused with those extra names of route try route -n so you just get the numbers.

fopetesl · 08-26-2009, 10:46 AM

Code:

# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 eth1
192.16.1.0      0.0.0.0         255.255.255.0   U     0      0        0 eth0
0.0.0.0         192.168.1.1     0.0.0.0         UG    0      0        0 eth1

and after route add -host 192.168.1.6 dev eth0

Code:

 route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.1.6     0.0.0.0         255.255.255.255 UH    0      0        0 eth0
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 eth1
192.16.1.0      0.0.0.0         255.255.255.0   U     0      0        0 eth0
0.0.0.0         192.168.1.1     0.0.0.0         UG    0      0        0 eth1

Code:

 ping 192.168.1.6
PING 192.168.1.6 (192.168.1.6) 56(84) bytes of data.
From 192.16.1.20 icmp_seq=2 Destination Host Unreachable
From 192.16.1.20 icmp_seq=3 Destination Host Unreachable
From 192.16.1.20 icmp_seq=4 Destination Host Unreachable

--- 192.168.1.6 ping statistics ---
6 packets transmitted, 0 received, +3 errors, 100% packet loss, time 4999ms
, pipe 3

Any help?

rn_ · 08-26-2009, 01:42 PM

Quote:

Originally Posted by fopetesl

Code:

root@machine:/home/Peter# echo !HH | nc 192.168.1.6 80
bash: !HH | nc 192.168.1.6 80: event not found
root@machine:/home/Peter#

The error you're seeing here is because of bash. You should put the !HH in quotes.

As for the routing, i think you're close, but instead of:

Code:

route add -host 192.168.1.6 eth0

try:

Code:

route add -host 192.168.1.6 gw 192.16.1.20

rn_ · 08-26-2009, 01:55 PM

i just noticed something; you have a 192.168.1 network and you also have a 192.16.1 (eth0) network; is that correct? and the ip address of the controller you're trying to communicate to has an ip address 192.168.1.6? or is it 192.16.1.6?

I think i missed some parts of your post. could you give us an overview of your nw again, with ip addresses and the specific route you're trying to setup?

evilted · 08-26-2009, 07:12 PM

after reading this, i have a question:

Are the two other ends of the cables attached to different physical devices? You may have looped your network and not even realized it...

if its routing:

Code:

route add -net 172.16.0.0 255.255.255.0 gw 192.168.0.x

where 192.168.0.x is the ip of the machine/router/gateway/switch/whatever hosting the other network.

Code:

for a host

route add -host 172.16.0.1 255.255.255.255 gw 192.168.0.x

you can also route through an interface, bit dodgy sometimes, but you can make the kernel look it up...

Code:

ip route add 172.16.0.0/24 dev eth0

etc, etc...

you cant exactly route a network your already on.
once you add a ip to a interface the network is already added in the routing table.

Code:

ifconfig eth0 172.16.0.1/24

route

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
172.16.0.0     *               255.255.255.0   U     0      0        0 eth1

maybe what your interested in is policy routing, but that would require different default gateways for the 2 interfaces.

if your cables are attached to different devices maybe device A is set to only allow access from eth0? and set to block everything else?

jschiwal · 08-27-2009, 05:18 AM

I have been misreading your IP address for eth0. It is on the 192.16.1.0 network. The device is on the 192.168.1.0 network.
Is 192.168.1.6 a typo?

Things would work out a lot better if your lan used 192.168.0.0 instead, or if you connected the device to a switch on the 192.168.1.0 LAN. This would eliminate the need for a host route.

One thing you could try is shut down eth1, and leave eth0 up on 192.168.1.20 and see if netcat works then.

fopetesl · 08-27-2009, 06:17 AM

Quote:

Originally Posted by jschiwal

I have been misreading your IP address for eth0. It is on the 192.16.1.0 network. The device is on the 192.168.1.0 network.
Is 192.168.1.6 a typo?

I do not know where 192.16.1.0 is derived from. I agree it looks like a typo and could probably be removed but as I said before I cannot find the file in which it resides.
192.168.1.6 is not a typo - it is the fixed IP address of the controller board hard linked into eth0.

Quote:

Things would work out a lot better if your lan used 192.168.0.0 instead, or if you connected the device to a switch on the 192.168.1.0 LAN. This would eliminate the need for a host route.

A switch is not an option because of the physical restraints and breaking backward compatibility.
Why would 192.168.0.0 be a better option?

Quote:

One thing you could try is shut down eth1, and leave eth0 up on 192.168.1.20 and see if netcat works then.

This is how it was previously and it works just fine with eth0 as the default gateway (even if eth1 is enabled).

zhjim · 08-27-2009, 07:39 AM

Quote:

Originally Posted by fopetesl

This is how it was previously and it works just fine with eth0 as the default gateway (even if eth1 is enabled).

After reading this I dare to say that if you would delete the 192.168.1.0/24 route on the eth1 device you should be set. The problem here is that if you need any other computer in this network.
This also might be done by completly deleting the routes to the 192.168.1.0/24 network on both devices and set up host routes for all computers you need/want to talk to.....

fopetesl · 08-27-2009, 08:16 AM

Quote:

Originally Posted by zhjim

After reading this I dare to say that if you would delete the 192.168.1.0/24 route on the eth1 device you should be set. The problem here is that if you need any other computer in this network.
This also might be done by completly deleting the routes to the 192.168.1.0/24 network on both devices and set up host routes for all computers you need/want to talk to.....

That sounds fine but if I had any idea how to modify the "default" routes already set up I would happily do so. As I already have said WTF are these routes set and in what file?
They certainly don't show in Network Manager GUI and none of the suggested paths/files contain this information.

jschiwal · 08-27-2009, 08:28 AM

Eth0 was set up with the wrong IP address. You probably mistyped it when configuring the device (by not typing the 8). Change it from 192.16.1.20 to 192.168.1.20.

I looked up "ubuntu configure routes" in google. Found this page:
http://www.ubuntugeek.com/howto-add-...in-ubuntu.html

zhjim · 08-27-2009, 08:31 AM

The routes for the 192.168.1.0/24 networks are setup automatical when the two devices get their IP and are set up (don't pin me on the order

). The default route normaly gets set through the dhcp client on eth1.
Take a look at /etc/network/if-up.d there are scripts that are run when a nic comes up. Just add your own script that kills the two route for the 192.168.1.0/24 network. Leave the default route as is and add a route to the 192.168.1.6 host...

Something like this.