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network interfaces

Nathan has published an interesting article at Linux.com about second Ethernet port:

Purchase a new PC or motherboard soon, and the chances are good that it will come with two built-in network interfaces -- either two Ethernet jacks or one Ethernet and one Wi-Fi. Tossing in a second adapter is an inexpensive way for the manufacturer to add another bullet point to the product description -- but what exactly are you supposed to do with it? If you are running Linux, you have several alternatives.

My second Ethernet port usage

What's your second Ethernet port usage?

Download of the day: Oracle VM

Virtualization is the process of abstracting computing resources such that multiple operating system and application images can share a single physical server, bringing significant cost-of-ownership and manageability benefits. Through its Oracle VM product, Oracle offers scalable, low-cost server virtualization for heterogeneous applications.

Oracle VM is free server virtualization software that fully supports both Oracle and non-Oracle applications, and is three times more efficient than other server virtualization products.
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XEN Server Status Monitoring Command Cheat Sheet

The xm command is the main command line interface for managing Xen guest domains. The program can be used to create, pause, and shutdown domains. It can also be used to list current domains, enable or pin VCPUs, and attach or detach virtual block devices.

Please note that before running any one of the following command you must run xend ( Xen control daemon aka service) and must be run as privileged user. Running xm command as non root will return an error.

I hope following XEN status monitoring cheat sheet will save your time.
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Q. I am using Ubuntu Linux and I would like to know how to create alias for eth0 so that I can have multiple IP address?

A. To create alias for eth0 use ifconfig command. It is use to configure a network interface and aliases.

Assuming that your eth0 IP is 192.168.1.10 and you would like to create an alias eth0:0 with IP 192.168.1.11. Type the following command:

sudo ifconfig eth0:0 192.168.1.11 up

OR

sudo /sbin/ifconfig eth0:0 192.168.1.11 up

Verify that alias is up and running using following two command(s):

/sbin/ifconfig
ping 192.168.1.11
ping your-getway-ip

Permanent configuration

Your ethernet configuration is located in a file called /etc/network/interfaces. If you reboot system you will lost your alias. To make it permanent you need to add it network configuration file:

gksudo gedit /etc/network/interfaces

OR

sudo vi /etc/network/interfaces

Append the following configuration:

auto eth0:0
iface eth0:0 inet static
name Ethernet alias LAN card
address 192.168.1.11
netmask 255.255.255.0
broadcast 192.168.1.255
network 192.168.1.0

Save the file and restart system or restart the network:

sudo /etc/init.d/networking restart

Please note that you can also use graphical tools located at System > Administration > Networking menu. Or use the following GUI tool to setup aliases, hostname, dns settings etc:

sudo network-admin

If you want more network aliases, use eth0:1, eth0:2, eth0:N (max upto 254).

See also:

Finally, today I had implemented NIC bounding (bind both NIC so that it works as a single device). Bonding is nothing but Linux kernel feature that allows to aggregate multiple like interfaces (such as eth0, eth1) into a single virtual link such as bond0. The idea is pretty simple get higher data rates and as well as link failover. The following instructions were tested on:

  1. RHEL v4 / 5 / 6 amd64
  2. CentOS v5 / 6 amd64
  3. Fedora Linux 13 amd64 and up.
  4. 2 x PCI-e Gigabit Ethernet NICs with Jumbo Frames (MTU 9000)
  5. Hardware RAID-10 w/ SAS 15k enterprise grade hard disks.
  6. Gigabit switch with Jumbo Frame

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I use ADSL at home via ISP modem. As soon as my eth0 comes up I would like to have my firewall script get executed and setup the iptables firewall rules for me.
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In this quick post I will explain how to add and configuring a network card under FreeBSD operating system using command line options.
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