Iperf Server Command

The server is a 64 bit job, the client a 32 bit job on an HP4400 that's well over a decade old! iPerf is generally testing the performance of a single flow or TCP connection through both. Only the port 5002 is opened to the outside. Iperf is a command line utility. The application is a frontend for Iperf, a popular command-line utility for bandwidth measurements. To measure the throughput of your network you need to run iperf client node which will connect to Iperf server. 3 and receive 1470 byte UDP datagrams from the client once the client is started. Iperf is a traffic generation tool that allows the user to experiment with different TCP and UDP parameters to see how they affect network performance. Depending on the service you are trying to manage you can use various different commands such as stop, start, restart, status, reload, kill etc. Iperf is a handy and reliable command line utility designed to measure bandwidth performance and to tweak various TCP related parameters, as well as UDP characteristics. I needed a task which would wake up my PC (if needed) and started an iperf server. I have a remote server with Ubuntu 14. Run Cygwin terminal on your laptop. in this way iperf will listen as a service on the default port, the 5201:. The commonly used iPerf commands are listed in the following table. From Data Domain CLI run : Destination: net iperf server run. x, you need to look at the server side output as it is generated there. You can also start your own Iperf3 server using the mlabbe/iperf3’s docker image or just refer to your iperf3 command’s man page. 0) - In PC, open console box and run "iperf -s" - In Mobile, Choose iperf client tab and type server's IP Press "Start" - iperf will run 10 seconds if -t option is not specified. This is done with the cd Downloads command. Do note that the ipef client connects to the iperf server through port 5001. Upload Test Perform tests with the following settings, replacing SERVER with the iperf server to which you are testing. Then go pick it up. I have written codes in c# which opens the cmd prompt, pass iperf parameters to start server side & client side. The server is a 64 bit job, the client a 32 bit job on an HP4400 that's well over a decade old! iPerf is generally testing the performance of a single flow or TCP connection through both. I'm trying to do network testing using iperf or netperf tools, and I'd like to be able to run both the client and server on the same computer. Running iperf -s will setup a basic Iperf server, you can also run Iperf in daemon mode by running iperf -D. The example below shows the results of an iPerf3 test run between a client and server through the Cumulus Linux switch:. What is Iperf? Iperf is a network performance utility that can generate both TCP and UDP traffic for testing bandwidth, latency, and packet loss. Server/Storage 1 Server/Storage 2. Iperf allows the tuning of various parameters and UDP characteristics. All Answers ( 3) Those are available at the server, either run-time or by reading the log the server generates. Running the server as a daemon Use the -D command line option to run the server as a daemon. When not specified, the default port is 5001. Iperf is a command line utility. For example, the following command initiates a TCP test against the specified server instance with 10 parallel connections: $ sudo iperf -c 192. iperf3: interrupt - the server has terminated BTW, I think non-zero receiver statistic is a bug - as iPerf client, Fortigate will act as a sender, not receiver. It's a client + server command line app that generates floods of packets and verifies they arrived on the other end. To start the iperf server in UDP mode, use iperf -sDu as the u specifies UDP; the startup message should indicate that the server is listening for UDP datagrams. Before running a test you will need to make of the hosts the iperf server. Iperf reports bandwidth, datagram loss, delay jitter. Command System. iperf –c -w1M *We will be running the commands vice versa so make sure to take note of the results. 3 and receive 1470 byte UDP datagrams from the client once the client is started. Run IPerf app on your android device Enter "-u -s" in the text box that appears saying "Iperf command line arguments" Press the button on the left top corner which reads "OFF" and turns "ON" to a green one on touching it. Iperf server. By the way -s stands for server and -c for client. Note that many iperf3 parameters have both short and long forms. The same iperf binary can be used to run the process in server and client modes. 3 to connect to the server on the AP. Open a command prompt (Start > Run > cmd). iPerf is a tool for active measurements of the maximum achievable bandwidth between two or more machines where an iPerf client connects to an iPerf server. client: 172. Also on most OSes using this option will also respond to IPv4 clients using IPv4 mapped addresses. Use iperf for quick and easy network tests. Setting up an end-to-end iperf test today requires we visit each endpoint and leave equipment there specifically to run iperf (we never have access to client servers to use). airstreamcomm. txt This command sets the server and outputs anything received to this server to the current working directory to the "10secserver. Measure network performance with Iperf/JPerf 802. After inputting this command, then click Enter to start measuring the speed. zip -n 500M -y C. IPERF Normally, the iperf client will send traffic to the server. The test will use 4 threads, each sending data and the test will be performed in both directions. Input "iperf -c - t 6000&". The Iperf tool is a freeware that can be run as executable file either in server or client mode. command iperf to measure network parameters of TCP (Transmission Control Protocol) connection and UDP (User Datagram Protocol) connection. On the recieve (server) side you can run a single iperf instances that will bind to all interfaces (this is the normal 'iperf -s' behavior), or exec multiple iperf servers, each using -B to bind to a specific interface (for finer-grained logging and control) as pileofrogs mentioned. Using Iperf: By default, the Iperf client connects to the Iperf server on the TCP port 5001 and the bandwidth displayed by Iperf is the bandwidth from the client to the server. iperf is a free and open source cross-platform command-line tool used for checking network performance in terms of bandwidth and speed. Download the iperf3 binary zip, unzip to a known location and open a command prompt in the folder where iperf3. It is particularly useful when experiencing network speed issues, as you can use iPerf to determine which server is unable to reach maximum throughput. The -P parameter runs ten worker threads to push the performance test to the max. Also, you can use -b to specify the sending rate. Iperf is a freely available tool which is present on all Avamar nodes which have been correctly kick-started. The latest version of iperf3 now supports disk to disk testing. Install Iperf and Test Network Throughput,Speed/Other Statistics September 19, 2014 Updated September 19, 2014 LINUX HOWTO , MONITORING Iperf is a network testing tool that can create TCP and UDP data connections and measure the throughput of a network that is carrying them. The test is over UDP. On the server side, simply run: iperf -s On the client side, run: iperf -c [server_ip] The client side will try to shove TCP packets through the network interface as quickly as possible for a period of 10 seconds by default. The output of ip -s link show up prints counters of all TX and RX packets. JPerf Client. The example below shows the results of an iPerf3 test run between a client and server through the Cumulus Linux switch:. First, go to https. If you changed the port to non-default, you can adjust it here. The problem is that the packets sent internally route (in the kernel) and not going out to the out side world (physical layer). You will need 2 computers on the same network, and the IP Address of one of them. lsb_release -a – get the version of Ubuntu uname -r – get kernel version uname -a – get all the information kernel Commands for Package Manager. How do I check the speed between the two Linux servers using command line options for private. iperf Testing on Network. The newer versions of iperf need this to fully stress the connection. I can saturate a gig network with using ttcp/iperf with a P4 for sure, P3 era boxes if the bus/network card is right (server class boxes- consumer boxes with P3 probably never had a network interface that could do gig line rate). My command was:. By Jim Tanous. It can test either TCP or UDP throughput. By default, the Iperf client connects to the Iperf server on the TCP port 5001 and the bandwidth displayed by Iperf is the bandwidth from the client to the server. This tutorial explains how to deploy a network service that uses iPerf. What is “iperf”? A software tool that examines the network bandwidth between 2 hosts. We’ll setting up 1 iperf client and 1 iperf server. iperf -s iperf --help Iperf is a very helpful tool written in C++ to measure network bandwidth and quality. Here is a diagram where Iperf is installed on a Linux and Microsoft Windows machine. An iperf3 server can be started using either of the -s or --server command-line parameters, for example: iperf3 -s. How to install iperf on Ubuntu 16. iperf validates udp connectivity and throughput. This is blog post number 4, on try to run Iperf on Android, my previous attempts were: Method 1 - getting the Google Play Store on a CyanogenMod phone and downloading the Iperf for Android application ; Method 2 - SSHing into an Android phone and trying to run Iperf from the command line. txt This command sets the server and outputs anything received to this server to the current working directory to the "10secserver. You can also start your own Iperf3 server using the mlabbe/iperf3’s docker image or just refer to your iperf3 command’s man page. To confuse things, there's an iperf2 and an iperf3. This group includes Process, Threads, Kernel and User Image Load/Unload, Disk I/O, DPCs and Context Switch events. The commonly used option with Iperf for RHA are as below:--s Start as server ( Always on the Master )-c start as client ( Always on the Replica)-w Window size ( TCPSendRecieve Window size in RHA)-l Buffer ( Chunklentgh in RHA)-p specificy number of multiple connections ( Streams in RHA). Iperf is a handy and reliable command line utility designed to measure bandwidth performance and to tweak various TCP related parameters, as well as UDP characteristics. List of all public iperf3 servers. name being the server that you are testing to. Iperf doit être lancé sur deux machines se trouvant de part et d'autre du réseau à tester. Iperf reports bandwidth, delay jitter, datagram loss. exe; in the cmd dialog box, input the command "Iperf3 -c 192. The Server or the Client can be linux or windows. You can also spot the -w 712KB. Iperf is a great tool to test bandwidth on both UDP (connectionless) and TCP. If passed through the client command, the outgoing interface will be set. (iperf command is available). The following example sets a large send and receive buffer size to maximise throughput, and performs a test for 60 seconds which should be long enough to fully exercise a network. This is a small "How to" for checking a service is running in the server or not. iPerf is a command-line tool used in diagnosing network speed issues by measuring the maximum network throughput a server can handle. Configuration. This system accepts the communication from the Iperf client. iperf -c (ip address or name of target server) -t 10 -P 10. List of all public iperf3 servers. It is purely command line and that explains the reason why only a few people use it. You can find out various settings and options for iperf by typing iperf –h. Iperf can be installed very easily on most used OS Platforms, in basic configuration (with two hosts, identifying a link) one host must be set as client, the other one as server. , the iPerf output included below is from a test to a publicly available iPerf server, bouygues. To connect to the remote host, add it's IP address after the -c switch. Features: * Measure bandwidth, packet loss, delay jitter * Report MSS/MTU size and observed read sizes. (It also reports that the default TCP window size is 64. On the “server” PC open a cmd prompt and navigate to the folder containing iperf. Usually iperf client send data to iperf server, what I need in this case is the server send data back to the client in the same connection. To perform an iperf test the user must establish both a server (to discard traffic) and a client (to generate traffic). Iperf is available for Windows, Arch Linux, Ubuntu, Android, iOS, and more. name being the server that you are testing to. There are several Iperf tutorials online to go deep into Iperf based testing. I am unable to set the bandwidth on both sides using the Iperf tool. It is the industry standard tool for checking the interface and uplink and port speeds that IaaS providers (aka Cloud companies like IBM Softlayer, Rackspace, AWS) advertise. Install iperf on both pfsense. See iperf documentation for details. Ubuntu/Lubuntu --- How to install & use iperf/jperf tool About open source tool “iperf”, it is a best choice for measuring TCP/UPD bandwidth performance because it allow us to change TCP/UPD parameters and report bandwidth/Jitter diagram. The tool is available on many platforms including Windows and Android. The directory listing is done with the Is command. The simplest test you can do with Iperf is a basic TCP test. Reverse dependencies ( 0 ) Reverse dependencies are Solaris packages that depends on iperf. 12 -f k -t 20 With the appropriate IP settings this time, only 121Mbps TCP throughput… poor me. Server side is ip address 192. iperf has the notion of a "client" and "server" for testing network throughput between two systems. Making GENI Experiments Repeatable and Replicable server and start iperf server iperf_client. net, TCP port 5001 TCP window size: 16. The test will use 4 threads, each sending data and the test will be performed in both directions. Command set 1 VM 1 (Server on IP 10. Iperf is a free software tool that can measure the bandwidth between two nodes in a computer network and the quality of a network link. gz The presentation opens the command prompt as shown. Related articles There are no recommended articles. What is “iperf”? A software tool that examines the network bandwidth between 2 hosts. Download iperf; Extract the downloaded folder to C:\Temp\iperf-3. Using iperf on a Microsoft Windows system Iperf is a free open-source software tool that provides a capability to measure the throughput between two hosts using both Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) data streams. I need to make sure clustered file system performance is reasonable as my servers shared with other users. One is the client (sender) and the other is the server (receiver). The test is over UDP. The -w option of iperf allows specifying units such as K (kilobytes) or M (megabytes). Performs a TCP upload then download between the client and server. zip -n 500M -y C. [2] Execute the command on the Server like follows. iperf is a free and open source network testing utility that allows you to measure the speed of IP networks. Lets test the throughput from the Linux client machine, as shown below:. A bandwidth intensive ping. The command string extends to the end of the line, and is executed with the user's shell. iperf is a strain test for networks/memory/disk, but is commonly used to find network problems. yum install iperf --enablerepo=dag and for the future if you are looking some rpm but you are not sure where it is or in which repo try (i was looking for iperf for you like this) Code: [Select]. The server is configured to use bonding in balance-alb mode, but in this test only one interface comes into play because the iperf client only gets a connection from one MAC address. You may need to know this if you need to configure your firewall to map traffic for the iPerf port to your iPerf server. On the “server” PC open a cmd prompt and navigate to the folder containing iperf. If you want to use UDP tests, use the -u argument. (iperf command is available). Easily deployed on your. The newer versions of iperf need this to fully stress the connection. iperf -s -D > iperfLog. (It also reports that the default TCP window size is 64. Iperf can be used in Windows, Linux, and MAC etc operation system. The above command, starts iperf server on the Windows machine, and it by default runs on the port 5001 by default. They run either CentOS or Ubuntu Linux. https://iperf. Note on computers running Win7 or Win2008 I recommend running the cmd prompt in elevated mode. 1 -P 99 --incr-dstip I've been doing a bit of fix ups in iperf 2. Here are the commands you need to get started, from the server side you only need a few commands these are below. Lab 2: Iperf Command Objectives Being familiar with the command iperf. In such case results we got during the test:. In addition, you need to setup iperf to run on 2 machines: the 'client' and the 'server'. The cl-netstat command adds this functionality, and can track individual connections under controlled environments. iperf works in a client/server model: one iperf command is run on one server in server mode, one iperf command is launched on another server in client mode. Iperf is a very useful utility for network troubleshooting. The sockstat -4 | more command gives an overview of the services running on the FreeNAS ® system. On the recieve (server) side you can run a single iperf instances that will bind to all interfaces (this is the normal 'iperf -s' behavior), or exec multiple iperf servers, each using -B to bind to a specific interface (for finer-grained logging and control) as pileofrogs mentioned. In the following examples a number of command line switches are used when running IPerf. The server runs on the remote host and listens for connections from the client. IPERF and TCP window size The TCP window size can affect the results of an IPERF test and mislead a user on a network's performance capabilities. gz [email protected] ring2014a tar xzvf ape rf-3. x, you need to look at the server side output as it is generated there. The output format is determined by the server (in particular, if the server was invoked with the --json flag, the output will be in JSON format, otherwise it will be in human-readable format). $ sudo apt install iperf -y. API - Documentation on readthedocs. iperf - c servername - p 80 (server requires same option) Performs a TCP upload from the client and server on TCP port 80. #iperf -c -w1M *We will be running the commands vice versa so make sure to take note of the results. Iperf is the robust tool to measure wired and wireless networks bandwidth throughput measuring on TCP/UDP. To perform an iperf test the user must establish both a server (to discard traffic) and a client (to gen- erate traffic). –t 30=> run the test for 30s) –-P: TCP session (Ex. sudo apt-get install iperf – on server side: iperf -s – on client side: iperf -c IPADDRESS -f k. It is purely command line and that explains the reason why only a few people use it. Iperf is a bandwidth tool. Specifies the command to use to connect to the server. Specify the server's IP address and port (default port is 5001). with iperf 2. 1 as the address of my Iperf server. iperf is a handy application allowing easy client-server setup, and able to measure network bandwidth, jitter, and packet loss ratio. When not specified, the default port is 5001. exe -s MACHINE2 - Iperf Client. Command set 1 VM 1 (Server on IP 10. 02 Network performance measurement graphical tool JPerf Iperf command: I -p 5001 s s s s s s s s s s s 0. It will run in the background just waiting for connections from iPerf Clients. In the command prompt on the server side, run this command. exe – c -P 10 -w 1000k " was run: ( -P refers to the number of parallel TCP streams and –w refers to the TCP window size ) 4. This will have the iPerf Server running as a daemon and the server messages will be logged in the file iperfLog. I think it's prudent to have a source ID somewhere in the packet or payload, similar to how TCP and UDP have been defined. The client is connecting to port 5001 while the server is listening on port 5000. For help contact [email protected] When he launched the second pair of iperf Client - Server, total aggregated bandwidth was still around 3 Gbits/sec. Iperf measures the maximum network throughput a server can handle and reports the results back to you. iPerf is a nice tool for that. API - Documentation on readthedocs. The latest version of iperf3 now supports disk to disk testing. net with an interval of every two seconds and a total of twenty second of testing: iperf -c IPerf. After rebooting, try executing the command again and verify that it fixed your problem. Don't confuse about the difference) equip Iperf with graphical interface. If you are not sure if the traffic that you wish to test is UDP or TCP, run this command to determine which services are running on the FreeNAS® system:. Dual test is a very useful feature, and actually iperf2 has a small problem with it - it does not display the measured uplink (client->server) throughput, only downlink. Read Also : 16 Bandwidth Monitoring Tools to Analyze Network Usage in Linux. docker run -d --net=host benhall/iperf iperf -s. Running iperf -s will setup a basic Iperf server, you can also run Iperf in daemon mode by running iperf -D. By default Iperf is uni-directional and sends data from the client to the server. Iperf is an Open source network bandwidth testing application, available on Linux, Windows and Unix. First, go to https. I have a remote server with Ubuntu 14. That is a lot of kitten per seconds, and using Jperf we can produce plots using this time the appropriate configuration:. About the App. On the command line of the client machine, run something like this: iperf -c 10. You can also start your own Iperf3 server using the mlabbe/iperf3’s docker image or just refer to your iperf3 command’s man page. By running the Iperf software on two computers over a network, data flows are sent between the computers and measurements returned regarding the performance between the endpoints. Read Also : 16 Bandwidth Monitoring Tools to Analyze Network Usage in Linux. To start iperf in client mode (the sender) you would type "iperf -c 10. In this section we will generally use the short form of command-line flags, unless only the long form of a flag is avail-able. Iperf reports bandwidth, delay jitter, and datagram loss. The above command, starts iperf server on the windows machine, and it bydefault runs on the port 5001 by default. 1 -u -b 512k #source iperf -B 224. sudo docker run -it --rm --name=iperf3-server -p 5201:5201 networkstatic/iperf3 -s (as this will name the container correctly on your NAS) You should get feedback your iPerf3 server is running You can now run the iPerf client with something like the following transposing the for the IP address of your Synology NAS. Give Iperf some time to test the connection, after the test is done Iperf will present the results. Feb 17th, 2015 8:30 AM EST. Download Iperf from their official website. We can use man iperf command in Linux to get all arguments. LibreELEC Forum. To set up the server side, enter the following iPerf command: C:\> iperf -s-----Server listening on TCP port 5001. When I test with iperf I get 950Mbps all the time and between all servers, htpc and workstation. A key point to remember when testing bandwidth with Iperf is that Iperf consumes all bandwidth available between client/server via TCP, regardless of LAN, WAN, or VPN connection. 5 Client IP: 10. In this tutorial you will learn: How to install iperf on Red Hat Enterprise Linux 8. net, TCP port 5001 TCP window size: 16. It then starts up the "server" or receiver, runs the iPerf utility test to set up communication between the two hosts, and initiates the test. 04 (Xenial Xerus) is as easy as running the following command on terminal:. When I test with iperf I get 950Mbps all the time and between all servers, htpc and workstation. When he launched the second pair of iperf Client - Server, total aggregated bandwidth was still around 3 Gbits/sec. iPerf consists of one executable that can be run in server or client mode. Iperf reports bandwidth, delay jitter, and datagram loss. Now to run the test in the opposite direction simply reverse the commands on the client and server. Iperf is an essential tool for bandwidth calculation and monitoring. net runs a TCP Iperf server on the default port 5001; iperf. 1 is server side ip address. We give an overview of some of its basic features here. iperf -c Bi-directional simultaneous (test the speed both ways at the same time). The first command line that would be a keeper is used to start an iperf server listener process for client connection. The server is configured to use bonding in balance-alb mode, but in this test only one interface comes into play because the iperf client only gets a connection from one MAC address. Use iperf for quick and easy network tests. The -P parameter runs ten worker threads to push the performance test to the max. Now connect to that server with iperf as client, just find the correct server IP address and run the command bellow iperf -c 192. 62: 63 * Sending output to stdout now makes errors go to stderr, as per: 64 UNIX convention (#695). airstreamcomm. IPERF is a command line tool to measure TCP bandwidth from a client instance to a server instance. So psexec it is. The tool is helpful to check the health of the link, common thing people do is blame service providers when they face any issue but it's possible that problem could be at customer premises. On the other machine configure it as the client and input the IP in the “Server Address” field. Although iperf3 has a GUI of sorts the traditional way to run iperf is from the command line. The traffic goes through a VPN from customer network to our network. iperf is a tool for performing network throughput measurements. To run test, you need to run iperf in server mode in one of the server using command. command prompt automatically closes after open in my pc. 30", the "-c" means to set PC B as Iperf client, and the IP address behind "-c" is the IP address of the server. According to wikipedia Iperf "is a commonly used network testing tool that can create TCP and UDP data streams and measure the throughput of a network that is carrying them. This is bound to the host machine/node IP address via NAT thanks to the -p 5201:5201 mapping. It supports tuning of various parameters related to timing, buffers and protocols (TCP, UDP, SCTP with IPv4 and IPv6). 1-100 or equivalent. Run the following command on the Iperf client and wait for. The latest version of iperf3 now supports disk to disk testing. The above command will only list active services. iPerf must be installed on both terminals between which we must analyze band performance. iperf-s [options] iperf-c server [options] iperf-u-s [options] iperf-u-c server [options] DESCRIPTION iperf is a tool for performing network throughput measurements. docker run -d --net=host benhall/iperf iperf -s. This command is a wrapper for the interface counters provided in Linux. Generating Traffic With Iperf Basic Usage We give an overview of some of the basic features of iperf which is a traffic generation tool that allows the user to experiment with different TCP and UDP parameters to see how they affect network performance. Download the iperf3 binary zip, unzip to a known location and open a command prompt in the folder where iperf3. Example of iperf client command syntax in iperf 3. If you are not sure if the traffic that you wish to test is UDP or TCP, run this command to determine which services are running on the FreeNAS® system:. iPerf consists of one executable that can be run in server or client mode. When he launched the second pair of iperf Client - Server, total aggregated bandwidth was still around 3 Gbits/sec. The bottleneck was proven to be not on Iperf side. Iperf is an essential tool for bandwidth calculation and monitoring. 0 --parallel 10 -i 1 -t 60 [-p ] Using these specified iperf parameters, the output displays the interval (60 seconds) per client stream, the data transferred per client stream, and the. Make sure that port 5201 is opened in Windows firewall. Running iPerf Server in Daemon Mode. Iperf reports bandwidth, delay jitter, and datagram loss. On the server that will be receiving data, open an elevated command window and run the following command: "iperf. The quality of a link can be tested as follows: - Latency (response time or RTT): can be measured with the Ping command. Do note that the ipef client connects to the iperf server through port 5001. Then go pick it up. 10:6969 and prints out the test results. In my examples I'm using 192. Download iperf 3. iperf-s [options] iperf-c server [options] iperf-u-s [options] iperf-u-c server [options] DESCRIPTION iperf is a tool for performing network throughput measurements. Note that the server VM must be at one site and the client must be across the link between sites in order to measure bandwidth. EXE command should be in your toolkit. It supports both UDP and TCP and can either test bidirectionally or unidirectionally from each endpoint in a single command. I was aware that Iperf is a good enough tool to generate and measure multicast and unicast traffic but support for SSM was missing from current version. Now to run the test in the opposite direction simply reverse the commands on the client and server. The easy way. In order to use Iperf you’ll need to setup an Iperf server, Iperf clients can then connect to the server in order to run tests. Set up one side as a listening server and the other side as a client. Use Ctrl+C to stop the server once the data has displayed. (See further. My problem is when I run a individual bidirectional test. It is particularly useful when experiencing network speed issues, as you can use iPerf to determine which server is unable to reach maximum throughput. This causes the server to listen on a group address, meaning it sends an IGMP report to the connected network device. On the server side, simply run: iperf -s On the client side, run: iperf -c [server_ip] The client side will try to shove TCP packets through the network interface as quickly as possible for a period of 10 seconds by default. 11 client command: iperf -c 192. yum install iperf. I have logging devices which need to use iperf to test to their home base server. Iperf is a free software tool that can measure the bandwidth between two nodes in a computer network and the quality of a network link. gz [email protected] ring2014a tar xzvf ape rf-3. Run the following command on the server.