This website is supported, hosted and funded by Corelan Consulting - https://www.corelan-consulting.com. Please follow us on Facebook (@corelanconsulting) and Twitter (@corelanconsult). Corelan training schedules: https://www.corelan-training.com/index.php/training-schedules



Please consider donating: https://www.corelan.be/index.php/donate/


14,629 views

Bind network interfaces on Linux for redundancy, load balancing and performance

If you have multiple network interfaces in your linux machine (and ideally they have the same speed & duplex), you may want to ‘bind’ the adapters together to increase bandwidth and create some redundancy.

Before going into the details on how to set this up under Fedora/Openfiler/other… linux flavors, I’d like to give some info about bonding (port trunking) and the types of bonding under Linux.

Bonding allows you to aggregate multiple ports into a single group, effectively combining the bandwidth into a single connection. Bonding also allows you to create multi-gigabit pipes to transport traffic through the highest traffic areas of your network. For example, you can aggregate three megabits ports (1 mb each) into a three-megabits trunk port. That is equivalent with having one interface with three megabits speed.

The “bonding” project has identified 6 bonding modes. It is recommended to choose the mode that suits your environment best. Keep in mind, some bonding modes rely on certain switch capabilities, so make sure to pick the right mode.

mode=0 (balance-rr)

Round-robin policy: Transmit packets in sequential order from the first available slave through the last. This mode provides load balancing and fault tolerance.

mode=1 (active-backup)

Active-backup policy: Only one slave in the bond is active. A different slave becomes active if, and only if, the active slave fails. The bond’s MAC address is externally visible on only one port (network adapter) to avoid confusing the switch. This mode provides fault tolerance. The primary option affects the behavior of this mode.

mode=2 (balance-xor)

XOR policy: Transmit based on [(source MAC address XOR’d with destination MAC address) modulo slave count]. This selects the same slave for each destination MAC address. This mode provides load balancing and fault tolerance.

mode=3 (broadcast)

Broadcast policy: transmits everything on all slave interfaces. This mode provides fault tolerance.

mode=4 (802.3ad)

IEEE 802.3ad Dynamic link aggregation. Creates aggregation groups that share the same speed and duplex settings. Utilizes all slaves in the active aggregator according to the 802.3ad specification.

    Pre-requisites:

    1. Ethtool support in the base drivers for retrieving

    the speed and duplex of each slave.

    2. A switch that supports IEEE 802.3ad Dynamic link

    aggregation.

    Most switches will require some type of configuration

    to enable 802.3ad mode.

mode=5 (balance-tlb)

Adaptive transmit load balancing: channel bonding that does not require any special switch support. The outgoing traffic is distributed according to the current load (computed relative to the speed) on each slave. Incoming traffic is received by the current slave. If the receiving slave fails, another slave takes over the MAC address of the failed receiving slave.

    Prerequisite:

    Ethtool support in the base drivers for retrieving the

    speed of each slave.

mode=6 (balance-alb)

Adaptive load balancing: includes balance-tlb plus receive load balancing (rlb) for IPV4 traffic, and does not require any special switch support. The receive load balancing is achieved by ARP negotiation. The bonding driver intercepts the ARP Replies sent by the local system on their way out and overwrites the source hardware address with the unique hardware address of one of the slaves in the bond such that different peers use different hardware addresses for the server.

 

 

Here are the steps required to set up bonding on your system.

Let’s assume that you want to bind eth1 and eth2 together, using mode 5. The bonded interface needs to have IP 192.168.0.1

You basically need to modify 4 files :

/etc/modprobe.conf
#added for bonding
alias bond0 bonding mode=5 miimon=100
/etc/sysconfig/network-scripts/ifcfg-eth1
DEVICE=eth1
BOOTPROTO=none
ONBOOT=yes
MASTER=bond0
SLAVE=yes
USERCTL=no
/etc/sysconfig/network-scripts/ifcfg-eth2
DEVICE=eth2
BOOTPROTO=none
ONBOOT=yes
MASTER=bond0
SLAVE=yes
USERCTL=no
/etc/sysconfig/network-scripts/ifcfg-bond0
DEVICE=bond0
ONBOOT=yes
BOOTPROTO=none
IPADDR=192.168.0.1
NETMASK=255.255.255.0
USERCTL=no

 

Reboot the system, and it should work.

You can find more information about bonding on http://sourceforge.net/projects/bonding/

In case you were wondering why I mentioned Openfiler, which is not really a OS that should be used for general purposes, but at the current time, the bonding implementation in Openfiler is not really mature yet, so it is advised to set it up manually and things will work fine as well.

© 2007 – 2008, Corelan Team (corelanc0d3r). All rights reserved.

Related Posts:

Comments are closed.

Corelan Training

We have been teaching our win32 exploit dev classes at various security cons and private companies & organizations since 2011

Check out our schedules page here and sign up for one of our classes now!

Donate

Want to support the Corelan Team community ? Click here to go to our donations page.

Want to donate BTC to Corelan Team?



Your donation will help funding server hosting.

Corelan Team Merchandise

You can support Corelan Team by donating or purchasing items from the official Corelan Team merchandising store.

Protected by Copyscape Web Plagiarism Tool

Corelan on Slack

You can chat with us and our friends on our Slack workspace:

  • Go to our facebook page
  • Browse through the posts and find the invite to Slack
  • Use the invite to access our Slack workspace
  • Categories