[solved]Eth0 not working, adapter OK

[JusTertii]

Hey guys,

I've got a perplexing problem trying to network my laptop (running LM 17.2, cinnamon) & pc (Win 7). The goal is to be able to remote desktop from my pc into LM, which I believe can be done by VNC server. Problem is, my pc & laptop can't talk to each other over eth0. I know it isn't hardware, having used eth0 on both machines with different devices.

First, here's my network infrastructure:

Router: 192..168.0.1 [static]--> laptop, wlan0, 192.168.0.5 [static IP] --- all working normally (internet access ok)

Next I tried plugging in my laptop and pc with ethernet, both PCs set to auto-DHCP. This gave them IPv6 addresses, which I couldn't ping via the ping command... When I disabled IPv6, they were unable to negotiate an IPv4 address. No problem, I can assign one manually, right?

So I tried

Laptop eth0 192.168..60.1 --> PC 192.168.60.2 [I used different subnet to isolate PC from other net traffic... right?]
laptop gateway 192.168.0.1 pc gateway 192.168.60.1
subnet 255.255.255.0 same
dns 8.8.8.8 same

But it didn't work... Any ideas what I'm doing wrong? I tried pinging 192.168.60.2 [pc] from the laptop, unreachable. Same with .1 from the pc. But each could ping itself.

In case it makes a difference, here's my inxi -FzxN

Code: Select all

System:    Host: cameron-ThinkPad-X220 Kernel: 3.16.0-38-generic x86_64 (64 bit, gcc: 4.8.2) 
           Desktop: Cinnamon 2.6.13  Distro: Linux Mint 17.2 Rafaela
Machine:   System: LENOVO product: 4290CE3 version: ThinkPad X220
           Mobo: LENOVO model: 4290CE3 Bios: LENOVO version: 8DET69WW (1.39 ) date: 07/18/2013
CPU:       Dual core Intel Core i5-2540M CPU (-HT-MCP-) cache: 3072 KB flags: (lm nx sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx) bmips: 10365.4 
           Clock Speeds: 1: 2602.132 MHz 2: 2637.070 MHz 3: 2627.726 MHz 4: 2978.218 MHz
Graphics:  Card: Intel 2nd Generation Core Processor Family Integrated Graphics Controller bus-ID: 00:02.0 
           X.Org: 1.15.1 drivers: intel (unloaded: fbdev,vesa) Resolution: 1366x768@60.0hz 
           GLX Renderer: Mesa DRI Intel Sandybridge Mobile GLX Version: 3.0 Mesa 10.1.3 Direct Rendering: Yes
Audio:     Card: Intel 6 Series/C200 Series Family High Definition Audio Controller driver: snd_hda_intel bus-ID: 00:1b.0 
           Sound: Advanced Linux Sound Architecture ver: k3.16.0-38-generic
Network:   Card-1: Intel 82579LM Gigabit Network Connection driver: e1000e ver: 2.3.2-k port: 5080 bus-ID: 00:19.0
           IF: eth0 state: down mac: <filter>
           Card-2: Intel Centrino Advanced-N 6205 [Taylor Peak] driver: iwlwifi ver: in-tree: bus-ID: 03:00.0
           IF: wlan0 state: up mac: <filter>
Drives:    HDD Total Size: 496.1GB (10.8% used) 1: id: /dev/sda model: OCZ size: 480.1GB 
           2: USB id: /dev/sdc model: ImationFlashDriv size: 16.0GB 
Partition: ID: / size: 23G used: 12G (56%) fs: ext4 ID: /home size: 27G used: 20G (80%) fs: ext4 
RAID:      No RAID devices detected - /proc/mdstat and md_mod kernel raid module present
Sensors:   System Temperatures: cpu: 56.0C mobo: N/A 
           Fan Speeds (in rpm): cpu: 2908 
Info:      Processes: 207 Uptime: 3 days Memory: 1773.4/3729.6MB Runlevel: 2 Gcc sys: 4.8.5 
           Client: Shell (bash 4.3.11) inxi: 1.9.17 

[richyrich]

Question . . How does your Router know that you decided to use a different subnet ?

[JusTertii]

Question . . How does your Router know that you decided to use a different subnet ?

I have no idea... I know a little bit about simple networking, but it's certainly not my forte.

Honestly, I don't care if the pc never gets internet access... If it does, yay, if not, meh. All I want it to do is remote desktop into my laptop so I don't have to use its stupid touchpad and wee little screen.

To try and isolate the issue, I've also tried setting laptop eth0 to x.y.0.20 and pc to x.y.0.21, but that didn't help either. (I'll use x and y to be 192 and 168, because knowing me I'll write a typo).

[richyrich]

Suggestion, turn IPv6 to ignore on both machines, set each IPv4 to Auto-DHCP, Turn off both machines, now reboot the router and once it is fully up, start up both machines.

The router should then be able to recognize both, give each machine an IP address, and will allow communication between both.
(unless you have done something else that would prevent this . .)

You should end up with x.y.0.1 (router), x.y.0.21 (example number pc #1), x.y.0.22 (pc #2).

[JusTertii]

Nope, didn't work... Should it, for this type of network?

So my router is wifi only; I've got no cat6 cable connecting to it. My OP might not have described it properly (sorry about that).

Router connects to everything via wifi. One of these is my laptop. PC has no wifi capability, only ethernet. So, I've got cat6 cable connecting laptop and pc. I've tried drawing a diagram below..

wifi cat6
Router <-> laptop <-> pc.

Therefore, as I understand it, the router would never see the pc even if it's got auto-dhcp enabled, because there's no direct connection... Is that right? Sorry if it's not, networking isn't my forte.

[richyrich]

Apologies, no my suggestion will not work the way you now explain it.

At least now that the details are more apparent, a more experienced member in networking will have an idea what you want.

good luck,
richy

[JusTertii]

Cheers mate, thanks for helping anyway... Computers - great when they do what you want them to do, bad when they do what you tell them to do.

[FreedomTruth]

Router connects to everything via wifi. One of these is my laptop. PC has no wifi capability, only ethernet. So, I've got cat6 cable connecting laptop and pc. I've tried drawing a diagram below..

wifi cat6
Router <-> laptop <-> pc.

Are you using a crossover cable? I think that is required for this configuration; otherwise you may need to use a switch or router with ethernet ports.

[JusTertii]

Are you using a crossover cable? I think that is required for this configuration; otherwise you may need to use a switch or router with ethernet ports.

Not sure, but whatever it is, I've successfully used it to network two PCs together before.

[FreedomTruth]

Router: 192..168.0.1 [static]--> laptop, wlan0, 192.168.0.5 [static IP] --- all working normally (internet access ok)

Next I tried plugging in my laptop and pc with ethernet, both PCs set to auto-DHCP. This gave them IPv6 addresses, which I couldn't ping via the ping command... When I disabled IPv6, they were unable to negotiate an IPv4 address. No problem, I can assign one manually, right?

So I tried

Laptop eth0 192.168..60.1 --> PC 192.168.60.2 [I used different subnet to isolate PC from other net traffic... right?]
laptop gateway 192.168.0.1 pc gateway 192.168.60.1
subnet 255.255.255.0 same
dns 8.8.8.8 same

Not sure what else to tell you. For direct connect like this, manual configure is the way to go (since I doubt either computer is running a dhcp server). One thing left to try is delete the gateway address (on both computers), just leave it blank. Leave it in for wlan0 on laptop, to keep internet access on it.

[richyrich]

Question , have you tried turning wireless completely off, and setting each machine with a static IP for ethernet in IPv4 ?
(Eg: 192.168.0.10 , 192.168.0.11)

[JusTertii]

One thing left to try is delete the gateway address (on both computers), just leave it blank

setting each machine with a static IP for ethernet in IPv4 ?

Thanks guys, between the two of you, you set me on the right path... Turns out, there were a couple of problems...

On my laptop eth0, I had the subnet mask 255.255.255.255 instead of .0 (stupid mistake). Between steps, I also had the laptop eth0 at .0.19 and the PC at .60.2 ... Fixed both to be on the same subnet.

Pinging each machine from the other results in sub-ms pings, so everything's working as it should. Thanks for your help fellas, marking solved... Now I've just gotta get the VNC up and running - you may see me on another thread soon

Cheers,
JT