UB、RH、LD、FB……
Currently on the market more common 3、4Layer firewalls，Called the network layer firewalls，There Layer 7 firewall，In fact, the gateway proxy layer
forTCP/IPofSeven-layer modelSpeaking，The third layer is the network layer，Three-layer firewall in this layer of the source and destination addresses for testing。But for the seven firewalls，Whether you source port or destination port，What is the source or destination address，We will have to check all your stuff。[……]
1、Modify / etc / profile
1.1 :First, set the environment variable in this file;
1.2:Run the export command to load the new environment variable settings good environment variable.
#vim /etc/profile
2、Modifying .bashrc
# vim /root/.bashrc
export PATH=”Variable Path
3、straight[……]
To talk about unix / linux for file operations in these functions，These functions for linux basically meet our requirements in any document，
First talk about the open function
In linux you want to operate on the file must first open the file and then the corresponding processing，Why should we do it? That is because the process and not directly manipulate files between，To process the document operation[……]
UnixLittle understanding of architecture
It can be defined as a software operating system in the strict sense，The software controls the computer hardware resources，Provider operating environment for personal understanding of hardware and software wealthy。We call such software kernel (kernel），It is relatively small，Located in the center of the environment
Kernel system call interface is called (system calls) Shared libraries built on system calls[……]
============= bash shell to manage files ==============
create、copy、delete、mobile、View、edit、compression、Competence、Find
one、Features Linux directory structure
Windows: To organize a plurality of documents C:\ D:\ E:\
Linux: [……]
SELinux is "Security-Enhanced Linux"Abbreviation，Linux is a US National Security Agency, "NSA = The National Security Agency" and SCC (Secure Computing Corporation) developedExtended mandatory access control security module。
Generally expand partition：Need to be adjacent。
advantage：LVM makes it easier to manage disk space。If the file system needs more space，Available space volume groups which may be assigned to a logical volume，And you can adjust the size of the file system。If a disk error began to appear，You may be replaced by a disk volume group registered as physical volumes，And the logical volume range can be migrated to a new disk。[……]
JDK (Java Development Kit) is a Sun Microsystems product for Java developers。Since its launch Java，JDK has become the most widely used Java SDK。JDK Java is the core of the whole，Including the Java Runtime Environment、Java tools and Java Foundation Classes。The first step is to learn the Java JDK。[……]
This article will guide you with detailed steps to deploy C-language development environment under Linux，Due to numerous Linux distributions，Specific circumstances vary，As used herein, the classic example of RHEL5。
Linux C development kit can be installed under the yum service，You can also use iso CD installation source files via the command rpm，Here use is[……]
