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I have 3 computers, 2 of which are connected to the third. The two NICs in the one machine cannot both work at the same time: With eth0 up and ...
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  1. #1
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    Can't get 2 NICs working in one box


    I have 3 computers, 2 of which are connected to the third. The two NICs in the one machine cannot both work at the same time:
    With eth0 up and eth1 down, machine connected to eth0 can ping.
    With eth1 up and eth0 down, machine connected to eth1 can ping.
    With ether NIC up, if second NIC is activated, the second NIC can be pinged but the first cannot. If the first NIC is deactivated and then reactivated, it will be pingable but the other no longer will be.

    Code:
    # cat /etc/sysconfig/networking/devices/ifcfg-eth0
    ONBOOT=yes
    USERCTL=no
    PEERDNS=yes
    GATEWAY=192.168.128.4
    TYPE=Ethernet
    IPADDR=192.168.128.4
    DEVICE=eth0
    HWADDR=00:90:27:31:8b:67
    BOOTPROTO=none
    NETMASK=255.255.255.0
    
    # cat /etc/sysconfig/networking/devices/ifcfg-eth1
    ONBOOT=yes
    USERCTL=no
    PEERDNS=yes
    GATEWAY=192.168.128.4
    TYPE=Ethernet
    IPADDR=192.168.128.5
    DEVICE=eth1
    HWADDR=00:50:04:22:f6:9d
    BOOTPROTO=none
    NETMASK=255.255.255.0
    
    # cat /etc/modules.conf
    alias eth0 e100
    alias eth1 3c59x
    Both NICs are at interrupt 18 according to /proc/interrupts. I've set these to different interrupts (maybe incorrectly) but Fedora wants to make them the same. eth0 is on the motherboard. I have also tried an e100 NIC for eth1 but it seems to be the same result.
    Please advise what needs to be changed to get both NICs pingable at the same time. This is Fedora Core 1. I have had a similar or same problem with Slackware.
    /IMHO
    //got nothin'
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  2. #2
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    Plug-N-Play BIOS is set to "No"....
    /IMHO
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    ///this use to look better

  3. #3
    Linux Guru sarumont's Avatar
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    What's the output of 'route' at any given point during your NIC debacle?
    "Time is an illusion. Lunchtime, doubly so."
    ~Douglas Adams, The Hitchhiker's Guide to the Galaxy

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  5. #4
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    Quote Originally Posted by sarumont
    What's the output of 'route' at any given point during your NIC debacle?
    Code:
    both down
    Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
    127.0.0.0       *               255.0.0.0       U     0      0        0 lo
    
    eth0 only
    Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
    192.168.128.0   *               255.255.255.0   U     0      0        0 eth0
    127.0.0.0       *               255.0.0.0       U     0      0        0 lo
    
    eth1 only
    Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
    192.168.128.0   *               255.255.255.0   U     0      0        0 eth1
    127.0.0.0       *               255.0.0.0       U     0      0        0 lo
    
    both up
    Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
    192.168.128.0   *               255.255.255.0   U     0      0        0 eth0
    192.168.128.0   *               255.255.255.0   U     0      0        0 eth1
    127.0.0.0       *               255.0.0.0       U     0      0        0 lo
    I checked this with all combinations of before-after. "both up" applies to (eth0 working / eth1 not) and vice-versa.
    Quote Originally Posted by previously, I
    With ether NIC up, if second NIC is activated, the second NIC can be pinged but the first cannot. If the first NIC is deactivated and then reactivated, it will be pingable but the other no longer will be.
    I don't know if I was mistaken when I wrote that, or if something has changed: now, when the second NIC is activated, the first will continue being pinged, but the second will not work unless and until the first is deactivated.
    /IMHO
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  6. #5
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    Does it help if they're on different subnets? e.g. if eth0 is on 192.168.128.0 and eth1 is on 192.168.129.0?
    ---sxeraverx---
    Linux without a C Compiler is like eating Spaghetti with your mouth sewn shut. It just doesn't make sense.

  7. #6
    Linux Guru anomie's Avatar
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    Just curious, can you show the output of
    Code:
    ifconfig
    while you have both NICs up?

  8. #7
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    Quote Originally Posted by anomie
    Just curious, can you show the output of ....
    Code:
    eth0      Link encap:Ethernet  HWaddr 00:90:27:31:8B:67
              inet addr:192.168.128.4  Bcast:192.168.128.255  Mask:255.255.255.0
              UP BROADCAST MULTICAST  MTU:1500  Metric:1
              RX packets:0 errors:0 dropped:0 overruns:0 frame:0
              TX packets:0 errors:3 dropped:0 overruns:0 carrier:3
              collisions:0 txqueuelen:1000
              RX bytes:0 (0.0 b)  TX bytes:126 (126.0 b)
              Interrupt:18 Base address:0x1480 Memory:f4102000-f4102038
                                                                                    
    eth1      Link encap:Ethernet  HWaddr 00:50:04:22:F6:9D
              inet addr:192.168.128.5  Bcast:192.168.128.255  Mask:255.255.255.0
              UP BROADCAST MULTICAST  MTU:1500  Metric:1
              RX packets:0 errors:0 dropped:0 overruns:0 frame:0
              TX packets:4 errors:0 dropped:0 overruns:0 carrier:4
              collisions:0 txqueuelen:1000
              RX bytes:0 (0.0 b)  TX bytes:240 (240.0 b)
              Interrupt:18 Base address:0x1400
     
    lo        Link encap:Local Loopback
              inet addr:127.0.0.1  Mask:255.0.0.0
              UP LOOPBACK RUNNING  MTU:16436  Metric:1
              RX packets:587 errors:0 dropped:0 overruns:0 frame:0
              TX packets:587 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:0
              RX bytes:173142 (169.0 Kb)  TX bytes:173142 (169.0 Kb)
                                                                                    
    ppp0      Link encap:Point-to-Point Protocol
              inet addr:66.2.44.240  P-t-P:67.95.10.135  Mask:255.255.255.255
              UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1500  Metric:1
              RX packets:399 errors:0 dropped:0 overruns:0 frame:0
              TX packets:411 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:3
              RX bytes:338169 (330.2 Kb)  TX bytes:69413 (67.7 Kb)
    Quote Originally Posted by sxeraverx
    Does it help if they're on different subnets? e.g. if eth0 is on 192.168.128.0 and eth1 is on 192.168.129.0?
    I really don't think it will: do you have reason to think it might?
    /IMHO
    //got nothin'
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  9. #8
    Linux Enthusiast puntmuts's Avatar
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    Yes it probably will help. Routing could be confused because there are 2 routes to the same local subnet. I think a different network will resolve this. I'm not sure but it is the first thing I would try.
    I\'m so tired .....
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  10. #9
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    Code:
    # ifconfig
    eth0      Link encap:Ethernet  HWaddr 00:90:27:31:8B:67
              inet addr:192.168.128.4  Bcast:192.168.128.255  Mask:255.255.255.0
              UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
              RX packets:2275 errors:0 dropped:0 overruns:0 frame:0
              TX packets:2978 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000
              RX bytes:275038 (268.5 Kb)  TX bytes:229648 (224.2 Kb)
              Interrupt:18 Base address:0x1480 Memory:f4102000-f4102038
     
    eth1      Link encap:Ethernet  HWaddr 00:50:04:22:F6:9D
              inet addr:192.168.0.5  Bcast:192.168.0.255  Mask:255.255.255.0
              UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
              RX packets:1099 errors:0 dropped:0 overruns:0 frame:0
              TX packets:853 errors:0 dropped:0 overruns:0 carrier:3
              collisions:0 txqueuelen:1000
              RX bytes:106904 (104.3 Kb)  TX bytes:82378 (80.4 Kb)
              Interrupt:18 Base address:0x1400
    
    # route
    Kernel IP routing table
    Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
    xxxxxxxxxxxxxxx *               255.255.255.255 UH    0      0        0 ppp0
    192.168.128.0   *               255.255.255.0   U     0      0        0 eth0
    192.168.128.0   *               255.255.255.0   U     0      0        0 eth0
    192.168.0.0     *               255.255.255.0   U     0      0        0 eth1
    
    169.254.0.0     *               255.255.0.0     U     0      0        0 eth0
    127.0.0.0       *               255.0.0.0       U     0      0        0 lo
    default         xxxxxxxxxxxxxxx 0.0.0.0         UG    0      0        0 ppp0
    puntsmuts and sxeraverx, let me know what you'd like in the sig space below. Thanks very much.
    /IMHO
    //got nothin'
    ///this use to look better

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