To change the firefox, start from - about:config
How to make firefox ask me to choose whether to open or save links
tools>options>applications ; Find the program that you want changed. Change action to "Always Ask"
Friday, February 26, 2010
Monday, February 8, 2010
Switching & Routing
Difference b/w Switching & Routing.
In short, If packet forwarding is dependent on mac then your doing switching and if it IP then your doing routing.
Difference between L3 switch and a Router.
Router does forwarding through S/W algoritms whereas L3 does through inbuilt ASICs.
In latest trend, any forwarding done in h/w is named as a switch :-).
L2 switch is a bridge which forward the packets based on MAC address.
Switch is faster than a router because forwarding is built in h/w.
bridges can’t block a broadcast (where a data packet is sent to all nodes on a network). Broadcasts can consume a great deal of bandwidth. Routers are able to block broadcasts, so they provide security and assist in bandwidth control.
Switching:
Ethernet is fundamentally what we call a shared technology.And that is, all users of a given LAN segment are fighting for the same amount of bandwidth.
A by-product that we have in any Ethernet network is something called collisions. And this is a result of the fundamental characteristic of how any Ethernet network works.Basically, what happens in an Ethernet network is that many stations are sharing the same segment. So what can happen is any one of these stations can transmit at any given time.And if 2 or more stations try to transmit at the same time, it's going to result in what we call a collision.
It's also important to understand fundamentally how transmissions can occur in the network. There's basically three different ways that we can communicate in the network.
1. Unicast
2. Broadcast
3. Multicast
in shared bandwidth, Broadcasts Consume Bandwidth & Processor Performance.
References:
http://www.e-tutes.com/index.html
http://www.e-tutes.com/lesson8/networking_fundamentals_lesson8_1.htm
http://www.tcpipguide.com/
In short, If packet forwarding is dependent on mac then your doing switching and if it IP then your doing routing.
Difference between L3 switch and a Router.
Router does forwarding through S/W algoritms whereas L3 does through inbuilt ASICs.
In latest trend, any forwarding done in h/w is named as a switch :-).
L2 switch is a bridge which forward the packets based on MAC address.
Switch is faster than a router because forwarding is built in h/w.
bridges can’t block a broadcast (where a data packet is sent to all nodes on a network). Broadcasts can consume a great deal of bandwidth. Routers are able to block broadcasts, so they provide security and assist in bandwidth control.
Switching:
Ethernet is fundamentally what we call a shared technology.And that is, all users of a given LAN segment are fighting for the same amount of bandwidth.
A by-product that we have in any Ethernet network is something called collisions. And this is a result of the fundamental characteristic of how any Ethernet network works.Basically, what happens in an Ethernet network is that many stations are sharing the same segment. So what can happen is any one of these stations can transmit at any given time.And if 2 or more stations try to transmit at the same time, it's going to result in what we call a collision.
It's also important to understand fundamentally how transmissions can occur in the network. There's basically three different ways that we can communicate in the network.
1. Unicast
2. Broadcast
3. Multicast
in shared bandwidth, Broadcasts Consume Bandwidth & Processor Performance.
References:
http://www.e-tutes.com/index.html
http://www.e-tutes.com/lesson8/networking_fundamentals_lesson8_1.htm
http://www.tcpipguide.com/
Sunday, February 7, 2010
Linux
You know how telnet works in linux..
In general xinetd will be listening for general daemons like ssh & telnet. When telnet request comes, xinetd handovers the control to telnetd and it inturn starts login which
xinetd--->telnetd--->login--->shell
xinetd--->sshd--->shell
PAM: Pluggable Authentication Modules
PAM is a library.
Through the PAM we can customize our the authentication methods.
For example: telnet spawns login. login will be having dependency on libpam.so. libpam.so reads the configuration file where we can define our customized authentication method(as a library) or we can use default linux authentication method.
similar to login for telnet, sshd will be having dependency on libpam.so.
To know the installed packages in linux:
Fedora:
#yum list installed
#rpm -qa
Ubuntun:
#dpkg --get-selections
Linux repositories are at:
#ls /etc/yum.repos.d/* OR
#cat /etc/yum.conf
Installing firefox in fedora:
http://www.if-not-true-then-false.com/2011/install-firefox-5-on-fedora/
To add new search plugin to firefox:
cp cisco.xml /usr/lib64/firefox/searchplugins/
Difference between zombie & orphan process
In general xinetd will be listening for general daemons like ssh & telnet. When telnet request comes, xinetd handovers the control to telnetd and it inturn starts login which
xinetd--->telnetd--->login--->shell
xinetd--->sshd--->shell
PAM: Pluggable Authentication Modules
PAM is a library.
Through the PAM we can customize our the authentication methods.
For example: telnet spawns login. login will be having dependency on libpam.so. libpam.so reads the configuration file where we can define our customized authentication method(as a library) or we can use default linux authentication method.
similar to login for telnet, sshd will be having dependency on libpam.so.
To know the installed packages in linux:
Fedora:
#yum list installed
#rpm -qa
Ubuntun:
#dpkg --get-selections
Linux repositories are at:
#ls /etc/yum.repos.d/* OR
#cat /etc/yum.conf
Installing firefox in fedora:
http://www.if-not-true-then-false.com/2011/install-firefox-5-on-fedora/
To add new search plugin to firefox:
cp cisco.xml /usr/lib64/firefox/searchplugins/
Difference between zombie & orphan process
Subscribe to:
Posts (Atom)