[solved...sort of] Have internet but cannot access LAN

[gordon.cooke]

Edit: I have my network up now, so I marked it solved. But, its a bit of a lucky work around and i still dont know or understand the true root cause. So i learned nothing. See my post from today, 21 Oct.

I am having an issue from one computer where I can access the internet, but for some reason I cannot ping or communicate with any of the other computers inside my home LAN. Especially bothersome since the computer with the issue is my media and file share server for the house.

Background: The problem computer is 192.168.1.5 It is running a xen hypervisor with a bridge, xenbr0, through eth0 with a static IP. When I set this all up I had the computer located in a part of the house that I couldnt get a cable to, so the computer was connected over a short cat5 into an external wifi adapter. The kind with a built in router (wifi in and 4 ports ethernet out). Then over wifi to the wifi router in the house (192.168.1.1). This setup worked fine except for speed. FYI: I DHCP most everything else. The DHCP is set to hand out in the range .100 to .125. My VMs are static with addresses in range .20 to .29

I finally manage to fish a cable to where I needed it. First I tried swapping the adapter with a spare wifi router (192.168.1.1) to extend my wifi. (different channel, turn off dhcp, different ip...) Thats when this issue started. Took the 2nd router out so now the cable is directly from the main router to the computer.

From the problem computer, i can ping the router, 192.168.1.1, and ping http://www.google.com, but pinging other computers returns Destination Host Unreachable. From other my cell and laptop I can also ping the router and internet, but cannot ping to the problem computer 192.168.1.5. However- from the problem computer I can pin my wii. I tried rebooting the laptop (on Mint13), even rebooted into windows 7 on it- same issue.
I also rebooted the problem computer (192.168.1.5) and booted into a different install of LMDE on a different partition (not a Xen server just vanilla) and the same issue was present there. In that case I let it DHCP over eth0.

I tried clearing the arp cache on this computer. I cold rebooter my cable modem and router. Even reset router to factory defaults. Still same issue.

sudo arp-scan --interface=xenbr0 --localnet from the problem computer only returns hits on the virtual machines inside the bridge.

user@vmhost ~ $ route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default . 0.0.0.0 UG 100 0 0 xenbr0
link-local * 255.255.0.0 U 1000 0 0 xenbr0
192.168.1.0 * 255.255.255.0 U 0 0 0 xenbr0

I used the network tool to run a traceroute.
to the router i get 192.168.1.5 - 192.168.1.1 - 192.168.1.1
to google i get 192.168.1.5 - 192.168.1.1 - 192.168.1.1 - 67.59.255.245 to a bunch more
to my cell over wifi (192.168.1.103) I get 192.168.1.5 - 192.168.1.5 and it times out at 2998.807 on the second hop
to my wii over wifi (192.168.1.108) I get 192.168.1.5 - 192.168.1.108 - 192.168.1.108

Any ideas? On tuesday I can probbaly get a cable tester at work to check the cables, but with a good connection to the internet Im not expecting that tobe the source of the problem.

[cwsnyder]

I am assuming that you have already checked the workgroup naming and other problems. What seems to be the problem from your description is that you had two different DHCP networks interconnected by the 'wireless adapter' when you set up your server with a fixed local IP and routed that way, now you have one DHCP network. I think you are going to have to re-setup your server to get your network to recognize the server. I am thinking that your Wii basically is a nearly idiot-proof networking device that if it gets a ping-back on ANY device, even if it doesn't make sense to its previous setup, it will attempt to connect.

[gordon.cooke]

Thanks. Actually I haven't checked workgroups but that hasn't changed from when it did work.

I took a live cd of mint 13 and rebooted off of that. It used dhcp and got .100 for an ip. But still same issue. I would figure a live cd would be like a clean install.

My router used to be set to hand outleases 'forever' . So i always got the same ip on each device. I would have thought that thr factory reset would have wiped that, but after a I noticed I still had the same ip's being handed out. I just changed it to 30 min. Now im getting different ip's but so far same issue. I only used the soft reset through the web ui, perhaps i need to use the physical reset button?

Anyone know better what touting info is stored where that could be the issue? Is it in yhe hardware nic? Im the routr? Or just a config in tne os?

[gordon.cooke]

OK- update- tried the physical reset button on the router. Have live cd in the problem computer with dhcp. Still having same issue.

[cwsnyder]

I think you have gone beyond my level of experience.

[gordon.cooke]

Ok, LAN is working now. I wanted to minimize variables and see if the new cable running from the basement to the 2nd floor was the issue. I took the entire wifi router right up next to the computer and used a known good manufactured cable fromthe problem computer to the router. Bingo! I could ping the problem computer and all the vms from other devices over wifi and wired.

Must have something to do with the new cable running up two floors. But I am comfused why the internet would still be up? So I tried connecting the modem in the basement, over the new cable i ran, into the WAN port of the router (now upstairs on the 2nd floor) And I have internet access from everything too. Bonus- the wifi on the 2md floor seems a better placement, we get much better coverage on the second floor and same or better on the first floor. So that great. But at the moment my blue ray player has no internet since it is wired only and the cable is routed to the basement. I think i may try a 4 port wired only router there next to the modem, with the wifi where it is now on sexond floor and see how it goes?

So apparently this cable is good enough for the modem to push data across, but not good enough for computer to computer lan traffic??? Anyone have any ideas why or how that works?

[KirbySmith]

Does this cable have molded ends, or are they user assembled? Perhaps the cable works at the moment as a result of disturbing it.

Another possibility is if the LAN is not auto-detect and some of the conductors are open-circuited; the connection might run 100 Mbps to the modem but LAN components expecting and set for Gbps would not connect.

kirby