Linux - NetworkingThis forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.
Notices
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Get a virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! Whether you are a digital nomad or just looking for flexibility, Shells can put your Linux machine on the device that you want to use.
Exclusive for LQ members, get up to 45% off per month. Click here for more info.
ok, I have 2 computers, descartes and aristotle. Descartes is my main desktop machine, has 2 NICs, eth1 going out to the rest of the world via a LAN connection, eth0 going via crossover cable to aristotle. Aristotle is just a small machine I want to use for file storage and a bit of distributed computing.
Trouble is, I can't get them to ping each other, I think it must be somethign to do with my routing tables.
Descartes is 192.168.0.1, aristotle is 192.168.0.2, netmask 255.255.255.0
Pinging each other they get "destination host unreachable", despite the fact that using ifconfig I can see they actually recieve the bytes, RX bytes on one matches TX on the other.
Code:
bash-3.00# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
137.222.232.0 * 255.255.255.0 U 0 0 0 eth1
192.168.0.0 * 255.255.255.0 U 0 0 0 eth0
loopback * 255.0.0.0 U 0 0 0 lo
default hlbr2-s232.nwgw 0.0.0.0 UG 0 0 0 eth1
That's from descartes.
I know this should be simple but I've read HOWTOs and googled but can't find why it's not working.
Post the result of running '/sbin/ifconfig -a' as root on both machines (if one is windows, run 'ipconfig /all' from a command prompt)
you should have something like this on each machine:
Code:
Descartes:
eth0 Link encap:Ethernet HWaddr FA:FA:FA:FA:FA:FB
inet addr:192.168.0.1 Bcast:192.168.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
aristotle:
eth0 Link encap:Ethernet HWaddr FA:FA:FA:FA:FA:FA
inet addr:192.168.0.2 Bcast:192.168.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
The important parts are the inet addr on each set right and the Bcast and Mask are the same along with the word UP. For windows it should have something like:
Also, check to make sure the computers can ping their local network stack with 'ping 127.0.0.1' (this proves the networking is working) and then that they can ping their own IP addresses with 'ping 192.168.0.1' and 'ping 192.168.0.2' (this proves that each machine sees it's own network card is set up and working) and post if any of these pings fail.
Fairly sure, (note the TX and RX bytes on eth0, indicating that /something/ has happened on the hardware level).
They were networked (kinda) find when decartes was on windows. (although if I had ICS running every other ping would ping 1000ms and it would be laggy as hell, but that went away when I stopped sharing the net).
eth0: Davicom DM9102/DM9102A rev 64 at 0xd400, 00:60:6E:77:0A:7F, IRQ 11.
I have a feeling it's using the tulip (?) module.
The reason I think it's a routing problem is this: the TX from aristotle matches the RX from descartes, but the TX from descartes never reaches aristotle because it has RX bytes 0.
Originally posted by ror the TX from aristotle matches the RX from descartes, but the TX from descartes never reaches aristotle because it has RX bytes 0.
That sounds like a cabling problem, or in the worst case a bad network card.
edit - could also be a NIC driver problem
Also, the error message, "destination host unreachable" indicates that the system knows how to reach the network segment that the other computer is on but can't find the machine when it looks there. A routing problem usually returns the error, "destination net unreachable" although it is possible for routing problems to produce either message.
Thanks, I know the problem isn't with the other machine/NIC since I can network to that fine under windows.
so, that leaves eth0's NIC on my main machine, could it not be transmitting? it logs TX bytes ?
It's a tulip chipset/module and someone else said they were having problems with one of them the other day. But I don't really have a way of checking the NICs out. (I would swap eth0 and eth1 but my ISP lock the connection to a MAC address)
Originally posted by ror ...
They were networked (kinda) fine when decartes was on windows. (although if I had ICS running every other ping would ping 1000ms and it would be laggy as hell, but that went away when I stopped sharing the net).
That too sounds like a cabling problem, or a failing network card. I'd try a new cable just to eliminate that as a problem, maybe just borrow one to test. It would be a shame if a flakey cable made you lose hours of time fiddling with it.
Anyhow, type '/sbin/lsmod' as root and see if tulip is listed there, you could also try 'cat /etc/modules.conf' and see what alias eth0 and alias eth1 are.
Code:
root@kollins:~# cat /etc/modules.conf
alias eth0 e100
alias eth1 3c59x
alias sound-slot-0 sb
alias char-major-195 nvidia
is mine, e100 is an Intel Pro 100 and the 3c59x is a 3Com 3C905B-TX
I don't know much about the tulip driver but I've read posts here where people had problems with them.
You could also actually try swapping eth0 and eth1 temporarily just to see if it is something with the card (hardware or driver) which could probably be done by changing the aliases around in modules.conf and then rebooting. Just unplug The Internet and then change them back and plug it back in after you try to ping the two machines.
edit - another trick would be to run 'tcpdump -i eth0' on one machine while you try to ping it from the other, you should see something like arp who-has 192.168.whatever tell xxx and then a reply with a MAC address and then some icmp echo requests which are the actual pings.
I've seen similar posts on here from people never getting these cards to work so I assume the linux drivers for it just don't work, guess I'll go spend ten quid on a new card :/
Originally posted by ror ...forcedeth is my eth1....
Ahh so thats what's got all those guys over at the other forum in such a huff about NVidia!
Running only 3Com and Intel NICs on anything that has linux on it, I've never opened that can of worms trying to get an NVidia network card to work...good luck
Guess that's another thing to add to the list when I shop for a new motherboard since they usually have LOM now, that or shut off the onboard and throw a 3Com NIC in.
LinuxQuestions.org is looking for people interested in writing
Editorials, Articles, Reviews, and more. If you'd like to contribute
content, let us know.
