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Re: Second ethernet card seems to cause networking failure?



On Tue, 26 May 2009 18:20:07 +0200, Frank Miles wrote:

> Sure, can provide more info...
> 
> ============ /etc/network/interfaces :
> 
> auto lo
> iface lo inet loopback
> 
> # The primary network interface
> auto eth0
> #iface eth0 inet dhcp
> iface eth0 inet static
>          address xxx.yyy.zzz.32
>          network xxx.yyy.zzz.0
>          netmask 255.255.255.0
>          broadcast xxx.yyy.zzz.255
>          gateway xxx.yyy.zzz.100
>          pre-up /etc/iptables/iptables.sh start post-down
>          /etc/iptables/iptables.sh stop
> 
> # The secondary network interface
> auto eth1
> #iface eth0 inet dhcp
> iface eth1 inet static
>          address 192.168.42.100
>          network 192.168.42.0
>          netmask 255.255.255.0
>          #broadcast 192.168.42.255
>          gateway 192.168.42.100
> 
> =============== route result:
> 
> Kernel IP routing table
> Destination     Gateway         Genmask         Flags Metric Ref    Use
> Iface xxx.yyy.zzz.0   *               255.255.255.0   U     0      0    
>    0 eth0 192.168.42.0    *               255.255.255.0   U     0      
0
>        0 eth1
> 
> ===============
> 
> To reiterate:
> 
> * The fundamental breakdown involves communication over the eth0
>  	interface.  Things just seem to "hang" when trying stuff like apt-
get
>  	update.
> 
> * ssh'ing into this machine from another host (directly to the IP of
>  	this machine) always works.
> 
> * firewall is "unchanged"; well, ok, added:
>      $IPT -A OUTPUT -o eth1 ! -s 192.168.42.0/25 -j DROP $IPT -A OUTPUT
>      -o eth1 -s 192.168.42.0/24 -j ACCEPT $IPT -A INPUT -i eth1 ! -s
>      192.168.42.0/24 -j DROP $IPT -A INPUT -i eth1 -s 192.168.42.0/24 -j
>      ACCEPT
>  	All communication with 192.168.42.x devices is functional. Listing
>  	iptables -L -n -v shows eth0 where it should.
> * simply turning firewall off (allowing everything)
>  	does not (at least by itself) fix eth0 communication.
> 
> * as you can see, this is IPs are entirely static - no dhcp *
> "network-manager" not installed
> 
> Since turning eth1 entirely OFF seems key to restoring eth0 full
>  	functionality, I agree that somehow the system seems confused 
about
>  	which interface to use.
> 
> Any other thoughts/ideas welcome!
> 
>  	-f
> *

This may be a somewhat naive question, but ...

Do the HWaddr's reported by ifconfig correctly match the MAC addresses 
for both eth0 and eth1?

.... Rich


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