Cloud Applications

The O & M of Enterprise Linux systems has become the focus of enterprises. As an excellent open-source network operating system, it is very important to make full use of Linux tools and use corresponding methods to improve O & M efficiency. In the

I configured a bugzilla in the previous group because of project requirements, and encountered some minor problems in the middle, so I recorded the process. after several months of operation, I moved from the Internet to the intranet, these two

After CentOS is installed, only port 22 is enabled by default. if you want to open other ports, you need to open the required ports. For example, open the default port 80 for http edit iptablesvi/etc/sysconfig/iptables

Encryption mechanism: plaintext encryption: telnetftppop3 password unreliable sendmailNFSNIS information data unreliable rshrcp verification unreliable security mechanism: 1. random number generator (RandomNumberGenerater) /dev/random system

Preface I have long wanted to write an article on Linux security settings. One advantage of writing an article is that you can understand your own ideas, and you will be able to remember it if you forget to write an article later. This article is

First, introduce the principles of ftp in active and passive modes: What is the role of ftp? If you build an ftp server on the intranet for testing, you do not need to pay attention to it. it is very easy. there is generally no firewall between

When iptables uses an instance, let's first take a look at the interaction principle between the server and client. Services provided by servers with certain functions are always provided by specific background programs. In TCP/IP networks, this

1. disable all INPUTFORWARDOUTPUT to open only some ports. The following is the command implementation: iptables-PINPUTDROPiptables-PFORWARDDROPiptables-POUTPUTDROP and then use the command iptables-L-n to check whether the settings are correct. you

It is very convenient to install ftp on a Linux server to provide users with upload and download. However, if your server has enabled the iptables firewall, you need to set the ftp port. I have also used iptables to allow access from a port. why do

TcpDump remarks tcpdump usage explanation and comment abstract the first type keyword is about the type, mainly including host, net, port, such as host210.27.48.2, indicating that 210.27.48.2 is a host, net202.0.0.0 indicates that 202.0.0.0 is a

Port5060orport2727: // only 5060 packets with ports 2727 and 5000 are captured. // The maximum number of packets is 5000./home/lishilin/0713001.cap// the number of packets saved to/home/lishilin/is 0713001. cap if all packets on the server are

When iptables is enabled for 11gR2RAC, node downtime is usually handled. when installing a database, the vast majority of users require selinux and iptables to be disabled before installation. However, in the carrier's system, many security factors

1. the core idea of configuring a dynamic DNS server is to run multiple binds on the DNS server. each BIND provides resolution for users from different regions, therefore, each BIND should have different configuration files and domain files, and

Manually download the following package. after downloading the package, use yum to locally install yumlocalinstall -- nogpgcheck *. after rpmyum installation is complete, re-run the cloudera-manager-installer.bin to complete the installation (if the

TCPDUMP introduction for network management personnel, the use of sniffer can grasp the actual network conditions at any time, when the network performance drops sharply, you can use the sniffer tool to analyze the cause, find out the source of

Those who have used linux terminal will not feel unfamiliar with such a command prompt. in particular, they will be able to clearly know the host of their username in the multi-user status. However, there is a problem with it, that is, the directory

Crontab is a good entry in Wikipedia. Unfortunately, this address cannot be accessed by proxy in China. Although the introduction of Crontab is everywhere, after reading this entry in detail, we still have some gains. The Crontab name is from

1. configure a filter table firewall (1) to clear the original rules. whether or not you have enabled the firewall when installing linux, if you want to configure your own firewall, clear all the filter rules. [root @ tp ~] # Iptables-F clear the

By default, firewall rules deny and prohibit the transmission of data packets from an IP firewall in the IP firewall. three built-in filter rule chains are used. All data packets arriving at the interface are filtered according to the input rule

Netfilter (packet filtering mechanism): analyzes the network packets that enter the host, captures the packet header data for analysis, and determines the online connection as a mechanism for release or resistance. 1. the table is an iptables