Port forwarding allows remote computers, for example, computers on the Internet, to connect to a specific computer or service within a private local area network (LAN).In Linux kernels, this is achieved by packet filter rules in the iptables or netfilter kernel components. BSD and Mac OS X operating systems implement it in the Ipfirewall (ipfw) module.This is also useful (a little bit useful)... Read More »

Tracking down your network daemons is extremely easy if you use the right tools.Last week a reader asked the following question:"I'm having trouble tracking down a process that'srunning on my machine. When I run netstat -a, I see lots of things thatshould be there, but also the following:$ netstat -aActive Internet connections (servers and established)Proto Recv-Q Send-Q Local Address    Foreign Address   Statetcp        0     ... Read More »

Tonight, while i use my RHEL-9 and Fedora Core (newly downloaded) via VM-Player, i feel that my network speed is very-very slow. So i think that Whats the reason behind this? n How to gain my previous speed (increase the speed)?After some time, i finally decided that i must implement bonding technique on my RHEL-9.Bonding is creation of single bonded interface by combining... Read More »

Ok friends, after creating a large amount of files (but empty) in windows, now we can also create a empty file in linux too.For this purpose we must a single commands and ..........Trick : - # dd if=/dev/zero of=filename bs=1024 count=desiredExample to create a 1GB file:dd if=/dev/zero of=file_1GB bs=1024 count=1000/or/dd if=/dev/zero of=file_1GB bs=4096 count=250/or/dd if=/dev/zero of=file_1GB bs=2048 count=500Example to create a 2GB file:dd if=/dev/zero... Read More »

So you broke down and finally set up a Linux machine on your network.And this time it’s not a server! You’re running one of the more recentdistributions (let’s say either Ubuntu 10.04 or Fedora 13) with theGNOME desktop. Here’s the thing: you need to allow other users, thoseusing Microsoft Windows-based machines, to have access to specific directories on that Linux box. How do... Read More »

YUM (Yellowdog Updater, Modified) is a client command lineapplication for updating an RPM based system from an internetrepository (YUM "yum-arch" server) accessible by URL (http://xxx, ftp://yyy or even file://zzz local or NFS).The YUM repository has a directory of the headers with RPM info and directory path information.YUM will resolve RPM package dependencies and manage the importation and installation of dependencies. YUM is also... Read More »

Each major version of Linux has had a different firewalling software suite. 2.0 kernels had ipfwadm, 2.2 had ipchains, and 2.4 has iptables. (2.4 can support ipchains-style rules if you load the ipchains module.) Each offers great improvements from its predecessors. Iptables, aka Netfilter offers extreemly powerful network controls, and can route packets to and from different machines and ports in ways beyond belief... Read More »