On Wed, 2005-02-23 at 02:11 +0100, Mats Erlandson wrote: > Gentlemen, > > I have stopped the machine, removed the second ethernet card, rebooted > and in that process, through kudzu, removed the configuration for the > removed card. After system is up, I have verified that the > configuration files for card two are removed. I am now back to where I > was after having tried, for several hours, to get eth0 to talk to the > switch. The green lights are on at either and, the cable check on the > switch shows cable OK. The computer can talk to the other > computers/devices on the local network but cannot even ping the switch. > I am logged into the computer from my laptop (using ssh) and it works fine. > > The 'netstat -rn' output is now; > Kernel IP routing table > Destination Gateway Genmask Flags MSS Window irtt > Iface > 192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 > eth0 > 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 > eth0 > 0.0.0.0 192.168.0.1 0.0.0.0 UG 0 0 0 > eth0 > > and 'ifconfig' is; > eth0 Link encap:Ethernet HWaddr 00:0F:EA:5C:06:CF > inet addr:192.168.0.90 Bcast:192.168.0.255 Mask:255.255.255.0 > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 > RX packets:785 errors:0 dropped:0 overruns:0 frame:0 > TX packets:269 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:1000 > RX bytes:231079 (225.6 KiB) TX bytes:27185 (26.5 KiB) > Interrupt:201 Base address:0xc000 > > What is so strange, is that the computer can talk to all local addresses > except the switch (192.168.0.1) and two other computers on the local > network can talk to it, all obviously through the switch both ways. > This shows that the cabling is OK, and that the problem is probably in > the routing on the computer (not allowing it to connect directly to the > switch) or in the switch, not accepting communication from the > computer. The switch routes properly for the other computers on the > network and can be managed from either one (tested) but not from the > problem child. If I change the configuration on the computer to use > DHCP (and rebooting) the computer does not get (receive/accept) the DHCP > configuration and is thus 'dead', i.e. no communication to nor from any > computer. Therefore, until the communication to/from the switch is OK I > am using a static address. To eliminate hardware faults possible in the > ethernet port on the motherboard (eth0) I installed a network card, > tested to perform OK in another computer, and disabled the motherboard > port using the BIOS. With only an expansion ethernet card active in the > computer I made the same tests with the same results. This seems to > eliminate network card problem in the computer. My current setup is, as > per the first paragraph above, motherboard ethernet port only with > static address. Still no joy. I am at a loss. > > Regards, > Mats > > Rick Stevens wrote: > > > Mats Erlandson wrote: > > > >> Well, I did what you suggested, but, to no avail. The result is > >> still the same. By the way, the reason I put in the second card was > >> to be able to switch between two, which I already tried without > >> success. The vexing question is though that if I configure one or > >> both of the network interfaces for DHCP neither one picks up the DHCP > >> info. This works flawlessly on both the other computers. > >> > >> So, this new computer cannot communicate with the switch or the wide > >> area network through the switch, but, mysteriously, it can > >> communicate with other computers/devices on the local area network > >> routed through the switch. > >> > >> A feeling is that the switch is at fault. However, the hardwired > >> working computer does not mind a port switch on the router, it just > >> works, also after reboot. The switch must have taken a serious > >> dislike to the new computer :-). > > > > > > The trick is that you only want ONE NIC. Your routes are confused. In > > general, there should only be ONE route for each network and you had > > two. There should also only be one default route (shown as "UG" in the > > "flags" column of the "netstat -rn" listing). > > > > You should also keep in mind that what you think is eth0 may be eth1 and > > vice versa. Generally, the NIC furthest from the CPU in your > > motherboard is eth0, but not always (it depends on how the PCI bus > > probes out). If your motherboard has a built-in NIC, then it's usually > > eth0. > > > > I'd recommend you delete the file > > > > /etc/sysconfig/network-scripts/ifcfg-eth1 > > > > Then edit the file > > > > /etc/sysconfig/network-scripts/ifcfg-eth0 > > > > Since you will be using DHCP, you only need the following information in > > it: > > > > DEVICE=eth0 > > ONBOOT=yes > > BOOTPROTO=dhcp > > > > Also edit the "/etc/sysconfig/network" file and make sure you do NOT > > have a "GATEWAY=" line in it (your DHCP server will provide one). > > > > Next, enter the two commands: > > > > /etc/rc.d/init.d/network stop > > /etc/rc.d/init.d/network start > > > > Verify that you have a link between eth0 and your hub/switch/router > > (they should both have a green LED showing). The cable on the other NIC > > should be unplugged, just so you don't get confused. > > > > Once that's done, verify that eth0 came up and got an IP address: > > > > ifconfig eth0 > > > > You can also verify that the default route got set up. "netstat -rn" > > should only show a couple of lines. The "device" column should only > > have "eth0" in it. If "eth1" shows up, we have other issues. > > > > You should also check the contents of the "/var/log/messages" file as > > well as the output of the "dmesg" command to see if you're getting > > errors on the system setup. > > > > As far as "switching" NICs, I assume you mean as a failover method. > > Doing that manually is not necessarily a good idea. You'd need to bring > > down the "failed" NIC, destroy existing routes, purge ARP tables, then > > bring up the second NIC and wait for it to build routes. You can't do > > it "on the fly". > > > > There is a mechanism called "bonding" that allows you to tie the two > > NICs into a failover service. Linux has a bonding driver, but to make > > it work the hub/switch/router must also support support bonding. Very > > few (if any) SOHO (small home or office) units out there (e.g. D-Link, > > Linksys, AirLink) do. You'd need to go to a relatively high-end switch > > (3Com, Cisco, Extreme or HP) to get bonding support--and even then it's > > not that reliable (at least not on HP or 3Com) in my experience. > > ---------------------------------------------------------------------- > > - Rick Stevens, Senior Systems Engineer rstevens@xxxxxxxxxxxxxxx - > > - VitalStream, Inc. http://www.vitalstream.com - > > - - > > - Tempt not the dragons of fate, since thou art crunchy and taste - > > - good with ketchup. - > > ---------------------------------------------------------------------- > > > > > Are you getting your IP address from the DHCP server running on the DI-624 router? If not try it or move your IP address within the DHCP range of the router (default is 100-199). This is a shot in the dark. Also, verify that the router is not filtering your IP or MAC. Bob...
