[root@ashok-web network-scripts]# cat /etc/sysconfig/network-scripts/ifcfg-eth1 DEVICE=eth1 HWADDR=00:1E:0B:CC:11:FC ONBOOT=no TYPE=Ethernet IPADDR=192.168.1.10 NETMASK=255.255.255.0
[root@ashok-web network-scripts]# cat /etc/sysconfig/network-scripts/route-eth1 GATEWAY0=192.168.1.1
NETMASK0=255.255.248.0 ADDRESS0=192.20.248.0
These variables have "0" appended to their names so they don't overwrite the main settings. The gateway addresses are the first and second IPs below the broadcast address for your network configuration. Use the appropriate GATEWAY for your backup network subnet.
GATEWAY1= NETMASK1= ADDRESS1= GATEWAY2= ADDRESS2= NETMASK2=
traceroute -i eth1 www.example.com
Redhat Linux
The Linux interface for forcing these parameters is a little simpler (at least for Redhat and derivatives). To ensure that an interface always comes up with a certain configuration you make a change to this file (for eth0, change number for other interfaces):
Append this line to the file to force 100Mb Full Duplex with auto negotiation off
However, if your backup network is GigE, you have to leave it with autoneg on
ETHTOOL_OPTS="autoneg on"
That takes care of the permanent settings, to force a change immediately the ethtool command is used. It can also be used to obtain the current settings, as below
linux-web# ethtool eth0
Settings for eth0: Supported ports: [ TP MII ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full Supports auto-negotiation: Yes Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full Advertised auto-negotiation: Yes Speed: 100Mb/s Duplex: Full Port: MII PHYAD: 24 Transceiver: internal Auto-negotiation: on Current message level: 0x00000001 (1) Link detected: yes
The command to force 100Mb Full duplex would be
ethtool -s eth0 speed 100 duplex full
Cheers!
