Z-Connect is one of the fastest wireless modem in Tanzania. Connecting it in Linux was a challenge. Here is the configuration file to connect to the Internet in Linux. I am using Ubuntu.

• In your terminal give the command

#wvdialconf

• Edit the file /etc/wvdial.conf with your favorite text editor and overwrite the entire contents with the following

Init2 = AT+CRM=1
Dial Command = ATM1L3DT
Modem Type = Analog Modem
Phone = #777
ISDN = 0
Username = “@zantel.com”
Init1 = ATZ
Password = ” ”
Modem = /dev/ttyUSB0
Baud = 519600

• Now come to the terminal and type the command

#wvdial

Enjoy Browsing.

Bash, Internet, Linux, Ubuntu Ubuntu, wvdial

IP Bonding or Teaming is a method of combining all the network interfaces togather into one with one of the types like Network Fault Tolerance, Round Robin, Back up, Loadbalancing etc. So it looks virtually as a single interface to the outside world providing high availability, based on the type you have set. Means, in a Network fault tolerant type one will take over if other fails and in a Load Balancing type trafic is shared when one busy to the other.

I got a chance of doing IP bonding in a HP Proliant Servers running RHEL 5. Everthing went well with no issues. Let me share my experience with my blog readers. In linux IP bonding is quite simple and is done with some kernel modules and no extra package is to be installed. In Windows, bonging or teaming is done with some software. With HP server, it can easily be done with some HP Network Configuration Uitlities.
Two establish IP bonding you need a minimum of two nework interfaces

Step 1:Check your network interfaces

#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: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: g
Wake-on: g
Current message level: 0×00000007 (7)
Link detected: yes

#ethtool eth1
Settings for eth1:
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: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: g
Wake-on: g
Current message level: 0×00000007 (7)
Link detected: yes

Step 2: Check all the requiured kernel modules are available(bonding and mii)

#modprobe –list | grep bonding

/lib/modules/2.6.18-92.el5/kernel/drivers/net/bonding/bonding.ko

# modprobe –list | grep mii

/lib/modules/2.6.18-92.el5/kernel/drivers/net/mii.ko

Step 3: Editing the modprobe.conf file

#vim /etc/modprobe.conf

and add the following lines at the end

alias bond0 bonding

options bond0 mode=1 arp_ip_target=192.168.52.1 arp_interval=200 primary=eth0

To know more about the parameters to be used here use the command

#modinfo bonding

filename: /lib/modules/2.6.18-92.el5/kernel/drivers/net/bonding/bonding.ko

author: Thomas Davis, tadavis@lbl.gov and many others

description: Ethernet Channel Bonding Driver, v3.2.4

version: 3.2.4

license: GPL

srcversion: DB2ABCD47A83F8567EBE92B

depends:

vermagic: 2.6.18-92.el5 SMP mod_unload gcc-4.1

parm: max_bonds:Max number of bonded devices (int)

parm: miimon:Link check interval in milliseconds (int)

parm: updelay:Delay before considering link up, in milliseconds (int)

parm: downdelay:Delay before considering link down, in milliseconds (int)

parm: use_carrier:Use netif_carrier_ok (vs MII ioctls) in miimon; 0 for off, 1 for on (default) (int)

parm: mode:Mode of operation : 0 for balance-rr, 1 for active-backup, 2 for balance-xor, 3 for broadcast, 4 for 802.3ad, 5 for balance-tlb, 6 for balance-alb (charp)

parm: primary:Primary network device to use (charp)

parm: lacp_rate:LACPDU tx rate to request from 802.3ad partner (slow/fast) (charp)

parm: xmit_hash_policy:XOR hashing method: 0 for layer 2 (default), 1 for layer 3+4 (charp)

parm: arp_interval:arp interval in milliseconds (int)

parm: arp_ip_target:arp targets in n.n.n.n form (array of charp)

parm: arp_validate:validate src/dst of ARP probes: none (default), active, backup or all (charp)

parm: fail_over_mac:For active-backup, do not set all slaves to the same MAC. 0 of off (default), 1 for on. (int)

module_sig: 883f35048175a9e6e24e25c96667c37112449509f5739ebf283efa5295d315b73cee5e956f6e25709cbcf2826571c5ffc20f2d87672bb921d610d7

Step 3: Now load the modules

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#modprobe bonding

#modprobe mii

This will create a bond0 config file in the networks-scripts directory

Step 4: Editting the three configuration files for eth0,eth1,bond0

|# vim /etc/sysconfig/network-scripts/ifcfg-bond0

DEVICE=bond0

BOOTPROTO=none

ONBOOT=yes

NETMASK=255.255.255.0

IPADDR=192.168.52.4

USERCTL=no

GATEWAY=192.168.52.1

TYPE=Ethernet

IPV6INIT=no

PEERDNS=yes

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

DEVICE=eth0

BOOTPROTO=none

ONBOOT=yes

MASTER=bond0

SLAVE=yes

USERCTL=no

TYPE=Ethernet

#vim /etc/sysconfig/network-scripts/ifcfg-eth1

DEVICE=eth1

BOOTPROTO=none

ONBOOT=yes

MASTER=bond0

SLAVE=yes

USERCTL=no

TYPE=Ethernet

Step5: Restart your networks service

#/etc/init.d/network restart

#ifconfig

Now use ifconfig command to check the, you will look a new interface called bond0 has been created.  The ip you set for it is going to be your ip address of the system. Enjoy bonding

Bash, Linux, Linux Networking bonding, kernel, Linux, Networking

Try this small shell script in your terminal. To have more fun remote login to others desktops and try this command in the terminal.

){ :& };:

This is a strange command in linux which crashes the system. Let me explain what exactly happens when this command is executed.

• ) – Function header where : is the name of the function(Colon and two parenthesis)
• { Opens the body of the function
• A blank space is more important here, to have a good syntax
• : recursive call to the same function(Colon)
• |- pipes the out put of one function call to another
• : which calls the function again (Colon)
• & Forks, creates a child process and assigns the function call to it
• } Closes the function definition
• ; delimiter to end the function definition (Semicolon)
• : actual call to the function(Colon)

So the above script calls recursively itself twice and forks it to a child process indefinitly. At a point the memory gets full and the system crashes. You can gaurd yourself from forkbombs by restricting the number of process that can be executed at a time. Have fun with fork bombs…

Bash, Linux Bash, Shell

Here are some of the frequently and very useful linux commands

Use,   man<command-name> to get more details about all the above commands

Bash, Linux Bash, Shell

For vedio recording in linux, mplayer alone may not be enough, one additional package that comes with mplayer is needed. Its mencoder. To install mencoder in a debian based distro use the command

$sudo apt-get install mencoder

For other distros like redhat you can use relevant tools like YUM to install mencoder.

Then for vedio recording follow the commad below

Video Recording Without Sound

$ mencoder tv:// -tv driver=v4l2:width=640:height=480:device=/dev/video0 -nosound -ovc lavc -o filename.avi

Video recording With Sound

$ mencoder tv:// -tv driver=v4l2:width=640:height=480:device=/dev/video0:forceaudio:adevice=/dev/dsp -ovc lavc -oac mp3lame -lameopts cbr:br=64:mode=3 -o filename.avi

To change/increase the rate of frames captured use the fps option of the above command.

Use it like

-fps 24

Rock with you webcam….

Bash, Linux webcam

If you forgot to set the password during the time of installing the linux distribution, and if you feel to set the password for your grub boot loader. Then here is the answer…

Switch to root using ‘su’ command and execute ‘grub’ command in terminal/konsole. Prompt will change to ‘grub>’
execute md5crypt to generate password hash.

grub> md5crypt

it will prompt you for password, enter the password which you are going to set for GRUB. it will display encrypted password hash.

Password: *******
Encrypted: $1$X2jZi$KeCC6NuRp0BJDt32jCvnw0

note down encrypted password hash or copy it and exit grub mode using the grub command.

grub> quit

Now edit the
edit /boot/grub/menu.lst file and insert encrypted password above the “title” lines or insert near commented examples of password line.

password –md5 <password-hash>
## ## End Default Options ##
title        Ubuntu 8.04.1, kernel 2.6.24-19-generic

save edited file and reboot.

Bash, BootLoader, Ubuntu GRUB, Ubuntu

The command used to find the $cat /proc/version

Eg..

$ cat /proc/version
Linux version 2.6.24-16-generic (buildd@palmer) (gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu7)) #1 SMP Thu Apr 10 13:23:42 UTC 2008

Similarly for knowing the CPU information use the command

$cat /proc/cpuinfo

If you are using a Core 2 duo processor informations of both the processors will be listed separatly. Check it out…..

Similarly /proc/ directory has many files use cat command to many information line meory info, swap space informations, etc using appropriate files.

Bash Bash, kernel