Default Route question when there are two nic cards

John Austin ja at jaa.org.uk
Wed Oct 11 20:38:03 UTC 2006


On Wed, 2006-10-11 at 13:27 -0700, Styma, Robert E (Robert) wrote:
> I am working with a machine with two nic cards.  One is connected
> to the corporate network.  This is eth0.  The other was previously
> not connected to anything.  Everything worked fine.
> 
> In setting the machine up for some work I will have to do, I did the
> following:
> 1.  Plug a cable into the eth1 rj45 and into a small hub.
> 2.  Plug a laptop into that same small hub.
> 3.  Configure the laptop to IP address 192.168.55.55 with the gateway 192.168.55.50
> 4.  Using system-config-network, I brought up eth1 as 192.168.55.50 with the
>     default gateway of 192.168.55.55 (the PC).  That is all that is attached to the
>     other network.
> 
> The problem is that when I reboot, or service network restart, the default
> route ends up on eth1 (192.168.55.55).  I can correct it by hand and everything
> is OK.
> 
> I have been googling the newsgroups and poking around in the ifcfg-eth* files
> and have not seen a way to tell the system that the default route is on eth0.
> 
> I must be missing something simple, can someone point me in the correct direction?
> (nnn is to obscure our corporate network info)
> 
> ifconfig -a
> eth0      Link encap:Ethernet  HWaddr 00:0C:76:FD:6F:17  
>           inet addr:nnn.nnn.36.86  Bcast:nnn.nnn.37.255  Mask:255.255.254.0
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:132036 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:133639 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000 
>           RX bytes:51419035 (49.0 Mb)  TX bytes:96862625 (92.3 Mb)
>           Base address:0xa000 Memory:fb000000-fb020000 
> 
> eth1      Link encap:Ethernet  HWaddr 00:0C:76:FF:3A:51  
>           inet addr:192.168.55.50  Bcast:192.168.55.255  Mask:255.255.255.0
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:116 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:637 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000 
>           RX bytes:10202 (9.9 Kb)  TX bytes:62796 (61.3 Kb)
>           Base address:0xb000 Memory:fa000000-fa020000 
> 
> 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:42266 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:42266 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:0 
>           RX bytes:4674615 (4.4 Mb)  TX bytes:4674615 (4.4 Mb)
> 
> The following is how the routing looks after service network restart (or reboot).
> Then the two commands fix the problem.
> 
> netstat -r -n
> Kernel IP routing table
> Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
> 192.168.55.0    0.0.0.0         255.255.255.0   U         0 0          0 eth1
> nnn.nnn.36.0    0.0.0.0         255.255.254.0   U         0 0          0 eth0
> 169.254.0.0     0.0.0.0         255.255.0.0     U         0 0          0 eth1
> 0.0.0.0         192.168.55.55   0.0.0.0         UG        0 0          0 eth1
> [lcm-phx-07-n1.phx.lucent.com]: route del -net 0.0.0.0 gw 192.168.55.55 dev eth1
> [lcm-phx-07-n1.phx.lucent.com]: route add -net 0.0.0.0 gw nnn.nnn.36.1 dev eth0
> [lcm-phx-07-n1.phx.lucent.com]: netstat -r -n
> Kernel IP routing table
> Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
> 192.168.55.0    0.0.0.0         255.255.255.0   U         0 0          0 eth1
> nnn.nnn.36.0    0.0.0.0         255.255.254.0   U         0 0          0 eth0
> 169.254.0.0     0.0.0.0         255.255.0.0     U         0 0          0 eth1
> 0.0.0.0         nnn.nnn.36.1    0.0.0.0         UG        0 0          0 eth0
> 
> Robert E. Styma
> Principal Engineer (DMTS)
> Lucent Technologies, Phoenix
> Email: stymar at lucent.com / styma at swlink.net
> Phone: 623-582-7323  Cell: 602-478-0114
> Company:  http://www.lucent.com
> Personal: http://www.styma.org
> 
Mine is set in /etc/sysconfig/network

GATEWAY=148.197.29.254

but sometimes appears in all of the 

/etc/sysconfig/network-scripts/ifcfg-ethx's

Don't think there is any harm in having it in all of them - provided it
says the same thing!

John




More information about the fedora-list mailing list