Question about metric (ethernet interface config)

circus78 · 01-05-2015, 02:44 AM

Hi,

I have two NIC on this server. For example:

Code:

eth0: 1.1.1.1
eth1: 1.1.1.2

I have two separated config file in /etc/sysconfig/network-scripts, I mean ifcfg-eth0 and ifcfg-eth1.
The problem is that when I browse internet from this machine, traffic is originated by eth1 address (1.1.1.2).
I would like that primary address is 1.1.1.1.
I tried to manage that through "METRIC" parameter

Code:

# cat ifcfg-eth0
DEVICE=eth0
BOOTPROTO=static
ONBOOT=yes
IPADDR=1.1.1.1
NETMASK=255.255.255.0
ONBOOT=yes

METRIC=0

# cat ifcfg-eth1
DEVICE=eth1
BOOTPROTO=static
IPADDR=1.1.1.2
NETMASK=255.255.255.0
ONBOOT=yes
METRIC=1

but preferred route is still on eth1:

Code:

# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         1.1.1.254       0.0.0.0         UG    1      0        0 eth1

I can surely use iptables MASQUERADE to do this, but I'am looking for a clean solution

Can you help me?

dijetlo · 01-07-2015, 07:18 AM

What your describing sounds similar to ethernet bonding. Two adapters, 1 session. The difference being with port bonding the result is logically assigned a single adapter designation for administrtion

J Martin Rushton · 01-12-2015, 11:33 AM

I have several machines with multiple interfaces, but they are on separate networks. I prefer traffic between machines to pass over a private network, keeping the public one for external traffic. The parameters for the ifcfg-eth? file are:

DEFROUTE=yes
IPV6_DEFROUTE=yes

You'll need to experiment in your particular case.