Intel NICs, Cisco, autoneg, and borken-ness

[klussier at comcast.net]

Can you try more then just ping? Try tracerouting to another network to see where the traffic stops, or where it tries to go. Try using lynx to open a web page. Sometimes someone does something dumb on a router like disallowing ICMP, or, in Cisco's case, tuning on "ICMP-Helper", which I have seen to have the same effect as blocking ICMP (not very helpful...). Also, check the cable. You can have link light with but a single wire in a pair :-)

C-Ya,
Kenny

 -------------- Original message ----------------------
From: Paul Lussier <p.lussier at comcast.net>
> 
> Hi all,
> 
> I've got a system up running Debian and a 2.4.22 kernel. 
> The primary NIC is:
> 
>   eth1      Link encap:Ethernet  HWaddr 00:07:E9:0C:99:2D  
>             inet addr:10.0.0.11  Bcast:10.0.255.255  Mask:255.255.0.0
> 
> 
>   # netstat -rn
>   Kernel IP routing table
>   Destination   Gateway     Genmask         Flags   MSS Window  irtt Iface
>   10.0.0.0      0.0.0.0     255.255.0.0     U         0 0          0 eth1
>   0.0.0.0       10.0.0.1    0.0.0.0         UG        0 0          0 eth1
> 
> 
> 2 weeks ago I manually configured a second interface on this system to
> be on a second network.  I configured the second interface to be on
> 10.95.0.11/16:
> 
> 
>   eth0      Link encap:Ethernet  HWaddr 00:0C:76:14:02:42  
>             inet addr:10.95.0.11  Bcast:10.95.255.255  Mask:255.255.0.0
> 
>   # netstat -rn
>   Kernel IP routing table
>   Destination   Gateway     Genmask         Flags   MSS Window  irtt Iface
>   10.95.0.0     0.0.0.0     255.255.0.0     U         0 0          0 eth0
>   0.0.0.0       10.95.0.1   0.0.0.0         UG        0 0          0 eth0
> 
> Using ethtool, I can see that the NIC is hard-wired to be 100baseT/Full:
> 
>   # ethtool eth0
>   Settings for eth0:
> 
>           Supported ports: [ TP ]
>           Supported link modes:   10baseT/Half 10baseT/Full 
>                                   100baseT/Half 100baseT/Full 
>                                   1000baseT/Full 
>           Supports auto-negotiation: Yes
>           Speed: 100Mb/s
>           Duplex: Full
>           Port: Twisted Pair
>           PHYAD: 0
>           Transceiver: internal
>           Auto-negotiation: off
>           Supports Wake-on: umbg
>           Wake-on: d
> 
> This NIC is connected to a Cisco 4507 running IOS[1][2], which has
> autoneg turned off and that port set to (so I'm told) 100Mb/Full.
> When I bring up the interface, I have link on both the switch and the
> server, but I can't ping anywhere.  I can't ping the gateway,
> 10.95.0.1, nor can I ping the other 6 systems I have configured on
> this switch, 10.95.33.[23,25,26,27,28,29].  These other 6 systems can
> all ping each other and the gateway. The server can ping no one,
> including the gateway.  Since this is a /16, the gateway is the same
> for all systems, 10.95.0.1.
> 
> 2 weeks ago, I'm certain I had this interface configured *and* working
> just fine.  Today, nothing I've tried seems to work[3].  I've
> ifup/ifdown'ed several times, tried manually configuring the interface
> via ifconfig, manually set the interface 100Mb/Full, 1000Mb/Full,
> autneg, etc. and changing everything on the switch to correspond with
> these settings, and nothing works.  I get a link light on the switch
> and server *only* when 100Mb/Full is hardwired on the switch, so it
> seems logical that I need to set the NIC to that speed, but that
> doesn't work either.
> 
> dmesg, syslog, and kern.log all show:
> 
>  kernel: e1000: eth0 NIC Link is Up 100 Mbps Full Duplex
> 
> yet, still no ping...
> 
> Any ideas would be greatly appreciated.
> 
> Thanks,
> 
> Footnotes:
> ----------
> [1] (as opposed to CatIOS)
> [2] Full version info:
>        Cisco IOS Software, Catalyst 4000            
>        L3 Switch Software (cat4000-I9K91S-M), Version 12.2(25)EWA4,
>        RELEASE SOFTWARE (fc1)
> [3] Given that this is my core NFS server, rebooting is not an option :(
> 
> -- 
> Seeya,
> Paul
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