RHEL – Creating Stable Names for Network Interfaces

devicesethernetlinuxrhel

We have a RHEL 5.5 box with 8 interfaces. And the eth interface naming is flip flopping. Sometimes eth0 comes up on physical port 7th, and sometimes on another physical port.

We want the naming to be as per the sequence of PCI BUS. I did the research and found that

cat /sys/devices/pci0000\:00/0000\:00\:1e.0/0000\:07\:07.0/net\:eth0/address\

This locations have the mac address of the eth devices. So If I get "address" in sequence from this pci bus locations and put them in ifconfig-eth0 to ifconfig-eth7 in order of PCI BUS location, my eth naming will be stable.

I tried:

find /sys/devices/ -name "address"

but it does not bring any results. I don't know why…

Any help here?

Best Answer

Have you tried including the MAC addresses in the different ifcfg-ethX files for the various ethernet devices? Additionally you can control which device get's which ethX handle through udev's 60-net.rules file.

For example

# /etc/sysconfig/network-scripts/ifcfg-eth0

# Intel Corporation 82573E Gigabit Ethernet Controller (Copper)
DEVICE=eth0
BOOTPROTO=static
DHCPCLASS=
HWADDR=00:30:48:56:A6:2E
IPADDR=10.10.10.15
NETMASK=255.255.255.192
ONBOOT=yes

Then in the file /etc/udev/rules.d/60-net.rules:

KERNEL=="eth*", SYSFS{address}=="00:30:48:56:A6:2E", NAME="eth0"

I believe this information is used to keep the devices configured consistently from boot to boot.

Configuring more than one ethX device

To deal with more devices simply setup each devices corresponding /etc/sysconfig/network-scripts/ifcfg-ethX file, and add another line to the 60-net.rules file.

KERNEL=="eth*", SYSFS{address}=="00:30:48:56:A6:2E", NAME="eth0"
KERNEL=="eth*", SYSFS{address}=="00:30:48:56:A6:2F", NAME="eth1"

The above is how you do it in CentOS 5.X. The file changes in CentOS 6.x to 70-persistent-net.rules, and the format is slightly different too:

SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="54:52:00:ff:ff:dd", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"

References

keeping eth0 as ETH0. - pwrusr.com blog

Related Solutions

Debian – changing the names of network interfaces, debian wheezy

The articles you found are somewhat outdated. There is now an easy method to assign names to network interfaces, through Udev.

On Debian and derivatives (including Ubuntu), look out for a file called /etc/udev/rules.d/70-persistent-net.rules. This file is created by /lib/udev/rules.d/75-persistent-net-generator.rules with the help of the script /lib/udev/write_net_rules. Each time udev sees a new network device, it will assign it a new number and append that number to /etc/udev/rules.d/70-persistent-net.rules. That way, interface numbers are persistent across reboots, and will persist after a reinstallation if you restore /etc.

(If your distribution doesn't ship these files, look for them in the Debian package.)

If you want to give a meaningful name to an interface and you have /etc/udev/rules.d/70-persistent-net.rules, all you need to do is to edit that file and change "eth0" to "ethLan". Run udevadm trigger --sysname eth0 to rename the existing device after you've edited the file (I think this requires shutting down the interface). If you don't have that file, you can write the one-line matching yourself (the complicated scripts that Debian adds are only to do this automatically):

SUBSYSTEM=="net", DRIVERS=="?*", ATTR{address}=="01:23:45:67:89:ab", NAME="ethLan"

Debian – Packets not moving through linux ethernet bridge

This is a quite old question, but it might be helpful for others.

Linux bridge might drop packages, if not configured correctly. I had a likewise problem and could solve it with the following information:

In short, there are options to configure the bridge: e.g.

# do not query iptables for package routing
echo 0 > /proc/sys/net/bridge/bridge-nf-call-iptables

# no additional processing for multicast packages
echo 0 > /sys/devices/virtual/net/br0/bridge/multicast_querier
echo 0 > /sys/devices/virtual/net/br0/bridge/multicast_snooping