Hadoop-definitions of Computer Network PortsPort Introduction
The ports described in this article are all logical ports, which refer to the ports in the TCP/IP protocol. The port number ranges from 0 to 65535, for example, port 80 used to browse Web Services, port 21 for the FTP service.
Here we will introduce the logi
"Problem phenomenon"Three virtual machines, respectively, master,slave1,slave2, according to the online step configuration start Hadoop, is no datanode, from the Slave1 log, is due to the request was refuse dropped."Problem Solving"In Master's host file IP mapping, master is mapped to 127.0.0.1 by default and needs to be commented out. (Host file location/etc/hosts)127.0.0.1 localhost#127.0.1.1 Master10.0.10.229 slave110.0.10.228 Slave2Note: This deta
Install times wrong: Failed to execute goal org.apache.maven.plugins:maven-antrun-plugin:1.7:run (site) on project Hadoop-hdfs:an Ant B Uildexception has occured:input file/usr/local/hadoop-2.6.0-stable/hadoop-2.6.0-src/hadoop-hdfs-project/ Hadoop-hdfs/target/findbugsxml.xml
Common commandsNetstat-pan|grep 2809: View a specific port situationNETSTAT-NL | grep 110: View a specific port situationNETSTAT-AP: List the connected PID (process number) based on the above command, using this PID, you can use Kill to kill the connectionFor example: a connected pid=111 that wants to kick out uses KILL-9 111. Ok!NETSTAT-RN: Output Routing TableNmap 127.0.0.1: View native open ports, scan all portsNmap-p 1024 65535? 127.0.0.1: Scan sp
--0.0.0.0/0 0.0.0.0/0 TCP spt:22Now the Linux server only opened 22 ports, with Putty.exe test whether you can link up.Can be linked up, stating that there is no problem.Finally, don't forget to save your firewall settingsSave by Command: Service iptables saveIptables-a input-p TCP--dport 22-j ACCEPTIptables-a output-p TCP--sport 22-j ACCEPTDo some explaining to these 2 commands.The-a parameter is considered a rule to add an INPUT
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. then, we can see that all the settings have been dropped, 1. disable all input forward output and only open it to some ports.
The following is a command implementat
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 can see that all the settings have been dropped.
1. disable all input forward output and only open it to some ports.The following is a command implementation:
Iptables-P INPUT DROPIptables-P FORWARD DROPIp
input 2Delete the rule with INPUT Chain number 2.
Click iptables-L-n to check whether it has been cleared.5. Filter invalid data packetsAssume that someone enters the server or has a virus Trojan program, it can transmit data outside the server through port.This method is different from the normal access to port 22 and 80. The data it sends to the external server is not sent by visiting the webpage.The response packet.
We will disable all the packets that are not responded through the request a
The SELinux security control of Linux is used for ports in addition to the file system, which enables processes that are started as services to be monitored only on a specified number of ports. For the narrative convenience we call the controlled port.Nginx Monitor PortTo see which managed ports are currently executable:grep ' ^http_port_t ' http_port_t
Hadoop Foundation----Hadoop Combat (vi)-----HADOOP management Tools---Cloudera Manager---CDH introduction
We have already learned about CDH in the last article, we will install CDH5.8 for the following study. CDH5.8 is now a relatively new version of Hadoop with more than hadoop2.0, and it already contains a number of
CentOS commands for viewing IP addresses, modifying IP addresses on ports, and activating ports
You know, you get used to ipconfig in windows, and it is a lot of trouble to view IP addresses in CentOS;
The information collected today focuses on IP port problems:
View IPIfconfig eth0 → view the IP address, but the output information is moreIfconfig | grep 'bcast' → the output information should be much cle
software cannot find it. Please confirm the server first.Whether you are open and necessary. If not, disable it.
Close port 4899:Enter cmd (command below 98) in start --> run, and then cd C: winntsystem32 (your systemEnter r_server.exe/stop and press Enter.Then input r_server/uninstall/silence
To C: winntsystem32(system Directory], delete three files: r_server.exe admdll. dll radbrv. dll.
Port:
1. First, use the fport command to determine the location of the program listening on
From:http://www.myhack58.com/article/sort099/sort0102/2011/31781.htm1. Close all INPUT FORWARD OUTPUT only for certain ports.Here is the command implementation:Iptables-p INPUT DROPIptables-p FORWARD DROPIptables-p OUTPUT DROPThen use the command iptables-l-N to see if it's set up, good-looking to all DROPSuch a setup, we are only temporary, restart the server or will restore the original not set the stateand save with service Iptables saveSee information firewall rules Firewall rule is actually
Python scans server ports in batches, and python scans server ports in batches.
I wrote a simple Port Scan script in Python. The simple logic is as follows:
1. python DetectHostPort. py iplist.txt (stores the text of the IP address list to be scanned, one address per line)
2. Enter the scan port, scan time, and scan interval.
3. Output scan information.
The source code is pasted below. You are welcome to m
port number you found in the previous step, or you can use the taskkill/pid PID command to kill the process. {taskkill/pid + the process number you want to kill}Use TASKLIST/FI "pid eq 5764" command to view process number corresponding to process informationTomcat Port Occupancy workaroundIf the front-end port is not occupied and is later occupied, you can go to the D:\tomcat-5.5.26\bin to execute shutdown.bat, so that the occupied port is releasedNTSD cannot kill the process: only System,SMSS.
Query port number 80 to open: Firewall-cmd --query-port = the / TCPpermanently open 80 Port number: firewall-cmd--permanent--zone=public --add-port = the / TCPRemoving the 80 port number:firewall-cmd--permanent--zone=public --remove-port= TCP--zone #作用域 --add-port=80/tcp #添加端口 in the format: port/Communication protocol --permanent #永久生效, no failure after this parameter is restarted View firewall StatusSystemctlStatusFirewalld.serviceStart | Close | Restart FirewallSystemctl[ start|
Sometimes we have Tomcat installed on the service Linux server (port number 8080), and the company's requirement is to enter the URL without adding a port number to access it, which means that the browser has to access your Tomcat (port 8080) via port 80, for which there are two solutions:
1. The Linux system prohibits 10,241 ports from being used by non-root users, then you must log on with root to start Tomcat modified to port 80 (note: directly in
Step one, Windows view all portsClick Start in the lower left corner of the computer, then select the Run option, and then in the popup window, enter the "cmd" command to make the command prompt. Then we enter "Netstat-ano" in the window and press ENTER, which will show all the port usage. :Step two, query the specified port occupancyIn the window, continue to enter the "Netstat-aon|findstr" Prompt Port "", for example, the prompt port is 9088, then the input command is "NETSTAT-AON|FINDSTR" 908
[password]]][/M [module] |/svc |/v] [/FI Filter] [/FO format] [/NH]Describe:This tool displays a list of processes currently running on a local or remote machine.Parameter list:/S system Specifies the remote system to which the connection is connected./u [domain\]user Specifies the user context in which the command should be executed./p [Password] specifies the password for the provided user context. If omitted, promptInput./M [Module] lists all tasks that currently use the given Exe/dll name.I
The firewall sets open ports for external use, and the Firewall opens ports for external use.
When deploying the project today, I met another person in the project team who reorganized iis on the server. As a result, I couldn't access the subordinate project externally and found the setting method through some channels.
The following error is reported:
The reason is that the "Inbound ICMP rule" has bee
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