Tcp connection test

Author: w | 2025-04-24

Starting a TCP connection test. FortiTester tests TCP concurrent connection performance by generating a specified volume of two-way TCP traffic flow via specified ports. To start a TCP connection test: Go to Cases Performance Testing TCP Connection to display the test case summary page.

Starting a TCP connection test

There are several link integrity tests available: Ping Test TCP Connection Test DNS Lookup Test Device Cloud Connection Test You can use these tests to demonstrate that two-way communication is working over the mobile connection. Several tests are provided because different mobile networks or firewalls may allow or block Internet packets for various services. Select the appropriate test according to the mobile network constraints and your preferences. The link integrity tests are only performed while the mobile connection is established. If the mobile connection is disconnected, the link integrity tests are suspended until the connection is established again. For the link integrity tests to provide meaningful results, the remote or target hosts must be accessible over the mobile connection and not through the LAN interface of the device (if it has one). That is, you should configure the settings to guarantee that the mobile connection is actually being tested. You can modify the link integrity test settings at any time. These changes go into effect at the start of the next test interval. Ping Test Enables or disables the use of “ping” (ICMP) as a test to verify the integrity of the mobile connection. The test is successful if a valid ping reply is received in response to the ping request sent. The ping test sends 1 ping request and waits up to 30 pings for a reply. When a valid reply is received, the test completes successfully and immediately. You can configure destination hosts for this test. If the first host fails to reply to the ping request, the same test is attempted to the second host. If neither host replies to any of the ping requests sent, the test fails. The primary and secondary addresses may be either IP addresses or fully qualified domain names. Primary Address: First host to test. Secondary Address: Second host to test if the first host fails. TCP Connection Test Enables or disables the creation of a new TCP connection as a test to verify the integrity of the mobile connection. A successful test establishes a TCP connection to a specified remote host and port number. If the remote host actively refuses the connection request, the test fails. The TCP connection test waits up to 30 seconds for the connection to be established or refused. When the TCP connection is established, the test completes successfully, and the TCP connection is closed immediately. You can configure two destination hosts for this test. If the first host fails to establish (or refuse) the TCP connection, the same test is attempted to the second host. If neither host successfully establishes (or refuses) the TCP connection, the test fails. The primary and secondary addresses may be either Use this to test port 9001 on IP address 10.20.30.40:nc -z -v -u 10.20.30.40 9001When the connection is successful, the screen output is:Connection to 10.20.30.40 9001 port [udp/*] succeeded!TCPTo use netcat for checking a TCP connection, you can use this to test port 9001 on IP address 10.20.30.40:nc -z -v 10.20.30.40 9001When the connection is successful, the screen output is:Connection to 192.168.168.121 9001 port [tcp/*] succeeded!WindowsUDPTo use PortQry.exe for checking a UDP connection, you can use this to test port 9001 on IP address 10.20.30.40:portqry -n 10.20.30.40 -e 9001 -p UDPWhen the connection is successful, the screen output is:UDP port 9001 (unknown service): LISTENING or FILTEREDIn the PowerShell session, you can also see if the connection was successful. It will show you a PortQry Test Message:10.20.30.40:61199 PortQry Test MessageTCPTo use PortQry.exe for checking a TCP connection, you can use this to test port 9001 on IP address 10.20.30.40:portqry -n 10.20.30.40 -e 9001 -p TCPWhen the connection is successful, the screen output is:TCP port 9001 (unknown service): LISTENING The scriptBelow is the script. You can save it on the system you want to start a TCP or UDP listener.function New-Portlistener { [CmdletBinding(DefaultParameterSetName = 'All')] param ( [parameter(Mandatory = $false, HelpMessage = "Enter the tcp port you want to use to listen on, for example 3389", parameterSetName = "TCP")] [ValidatePattern('^[0-9]+$')] [ValidateRange(0, 65535)] [int]$TCPPort, [parameter(Mandatory = $false, HelpMessage = "Enter the udp port you want to use to listen on, for example 3389", parameterSetName = "UDP")] [ValidatePattern('^[0-9]+$')] [ValidateRange(0, 65535)] [int]$UDPPort ) #Test if TCP port is already listening port before starting listener if ($TCPPort) { $Global:ProgressPreference = 'SilentlyContinue' #Hide GUI output $testtcpport = Test-NetConnection -ComputerName localhost -Port $TCPPort -WarningAction SilentlyContinue -ErrorAction Stop if ($testtcpport.TcpTestSucceeded -ne $True) { Write-Host ("TCP port {0} is available, continuing..." -f $TCPPort) -ForegroundColor Green } else { Write-Warning ("TCP Port {0} is already listening, aborting..." -f $TCPPort) return } #Start TCP Server #Used procedure from $ipendpoint = new-object System.Net.IPEndPoint([ipaddress]::any, $TCPPort) $listener = new-object System.Net.Sockets.TcpListener $ipendpoint $listener.start() Write-Host ("Now listening on TCP port {0}, press Escape to stop listening" -f $TCPPort) -ForegroundColor Green while ( $true ) { if ($host.ui.RawUi.KeyAvailable)

TCP Connection Testing with Telnet - Pluralsight

MNet TCP Server/ClientNuGetJust a small lightweight library for TCP Communication in .NET/C#. It utilizes some techniques from internalkestrel sockets for some performance benefits. Some notes on things used:Remarks on used technologiesUses some "stackalloc" and "MemoryPool.Shared" for less heap allocationsUsage of "System.IO.Pipelines" for better bufferingCustom schedulers for TasksCustom "PinnedBlockMemoryPool" from kestrelExpression Compilation for better performance of eventsFor Secure Ssl falls back to SslStream under the hood, but still amazingly fastSimple UsageYou should always first register all the event handlers before calling Server.Start/Client.Connect, in order for you to not miss any instant messages.Creation of a TCP Servervar server = new TcpServer(new TcpServerOptions() { Address = "127.0.0.1", Port = 43434, Logger = debugLogger, // ILogger of your liking, default is just console one Serializer = new TcpJsonSerializer(), // by default TcpJsonSerializer, you can implement your own serializers with ITcpSerializer Handshaker = new TcpServerHandshaker(), // by default no handshaking, if you need handshaking implement a ITcpServerHandshaker});server.Start();Connect / Disconnect (Connect event is after successful handshake) { ...};server.OnDisconnect += (connection) => { ...};">server.OnConnect += (connection) => { ...};server.OnDisconnect += (connection) => { ...};Register event handler for raw bytes messages>("test-bytes", (buffer, connection) => { // important, will only work by using ReadOnlyMemory here, not byte[], Memory etc. Console.WriteLine("Length: " + buffer.Length); // send a raw bytes message (important for sending must be of type Memory) connection.Send("test-bytes", new Memory([0, 2, 3, 5]));});">server.OnReadOnlyMemorybyte>>("test-bytes", (buffer, connection) => { // important, will only work by using ReadOnlyMemory here, not byte[], Memory etc. Console.WriteLine("Length: " + buffer.Length); // send a raw bytes message (important for sending must be of type Memory) connection.Send("test-bytes", new Memorybyte>([0, 2, 3, 5]));});Register event handler for serializable messages("test-class", (obj, connection) => { if(obj == null) return; Console.WriteLine("Length: " + obj.ToString()); // send a serializable message connection.Send("test-class", new AnyClassOfYours() { A = "Wow!" });});">server.OnAnyClassOfYours>("test-class", (obj, connection) => { if(obj == null) return; Console.WriteLine("Length: " + obj.ToString()); // send a serializable message connection.Send("test-class", new AnyClassOfYours() { A = "Wow!" });});Creation of a TCP Clientvar client = new TcpClient(new TcpClientOptions() { Address = "127.0.0.1", Port = 43434, Logger = debugLogger, // ILogger of your liking, default is just console one Serializer = new TcpJsonSerializer(), // by default TcpJsonSerializer, you can implement your own serializers with ITcpSerializer Handshaker = new TcpClientHandshaker(), // by default no handshaking, if you need handshaking implement a ITcpClientHandshaker});client.Connect();Connect / Disconnect (Connect event is after successful handshake) { ...};client.OnDisconnect += () => { ...};">client.OnConnect += () => { ...};client.OnDisconnect += () => { ...};Register event handler for raw bytes messages>("test-bytes", (buffer) => { // important, will only work by using ReadOnlyMemory here, not byte[], Memory etc. Console.WriteLine("Length: " + buffer.Length); // send a raw bytes message (important for sending must be of type Memory) client.Send("test-bytes", new Memory([0, 2,. Starting a TCP connection test. FortiTester tests TCP concurrent connection performance by generating a specified volume of two-way TCP traffic flow via specified ports. To start a TCP connection test: Go to Cases Performance Testing TCP Connection to display the test case summary page. TCP connection state: When testing TCP connections, Test-NetConnection returns the TcpTestSucceeded property, which is a Boolean value indicating whether the TCP connection

TCP Test Failed - No Connectivity - Arista

IP addresses or fully qualified domain names. TCP Port: The TCP port number to connect to on the remote host. The default is 80. DNS Lookup Test nables or disables the use of a Domain Name Server (DNS) lookup as a test to verify the integrity of the mobile connection. The test is successful if the DNS server sends valid reply. Typically, this means the hostname is successfully “resolved” to an IP address by a DNS server. But even a reply such as “not found” or “name does not exist” is acceptable as a successful test result, because that demonstrates successful two-way communication over the mobile connection. When a valid reply is received, the test completes successfully and immediately. This test uses the primary and secondary DNS server obtained from the mobile network when the PPP connection is first established. You can view these addresses on the Administration > Mobile Status page. Note ">Note The LTE modem does not use a PPP connection. Device Cloud Connection Test Enables or disables verification of the Remote Manager connection. The test is successful if you can establish a connection to the configured Remote Manager server, and if you can exchange keep-alive messages with the server. The test fails if you cannot establish a connection or if keep-alive messages stop. You can configure the Remote Manager server on the Advanced Configuration > Device Cloud Connectivity page. © 2020 Digi International Inc. All rights reserved.Link integrity test options updated on 21 February 2023 11:04:01 AM Using less memoryConversely, if the proxy inspection is mandatory, consider changing the tcp window to dynamic.Disable NP offloading:On the new test firewall policy from above disable NP offloading functionality.This can help in cases where an NP may be faulty or encounter aberrant traffic.See this article for instructions. Then re-test.Check bandwidth availability.This is especially important for traffic traversing the internet.Check that the internet service at both ends of the connection is not saturated for both ingress and egress traffic.The best way to do this is likely by reviewing logs or running a report based on log data.Also, under FortiView -> Policies/Sources/Destinations there is some bandwidth information available.Example:If traffic is saturated, consider implementing a guaranteed traffic shaper for the traffic in question.Isolate from the internal network.In extreme cases, it may be beneficial to connect a test client and server directly to spare firewall ports and re-test after creating appropriate policies.Impact of Latency on TCP Download Performance. TCP is a reliable protocol for sending data accurately and in order, but its performance is affected by latency.The higher the round-trip time (RTT), the lower the TCP download throughput will be, even if the connection speed is high. For example, with a 1 Gbps link, the maximum possible throughput might only be 17.4 Mbps if the latency is 30 ms. This shows how TCP performance can be significantly constrained by latency.To estimate the maximum theoretical throughput of a TCP session, the following formula can be used: Throughput = TCP maximum receive windowsize / RTTThis ensures

Powershell – Test the TCP port connectivity

That includes the port number, provided unique test id and the test result. These are then broadcast to all listening web servers. The web server has the option, after a timeout, to consider ip/port combination in error separate from receiving a result from the distributor. This decoupling is intentional in case the distributor or other backend services encounter a problem during the test. As implemented this piece cannot scale. But observation of the processes under load shows that it can handle a significant number of web servers and children connected to it with reasonable resource utilization. It is helped immensely by not having to hold the state of any test, the data just passes through. If necessary this could be replaced with a distributed pub/sub system such as Redis or Simple Queue Service. Tester The tester runs on a separate server from the web server by design. This ensures that connections made to your machine do not come from netbymatt.com, where your firewall recognizes that you have an ongoing connection. Some firewalls have been observed to respond differently to unsolicited packets received from an ip address that has other connections active. By using a different server we eliminate this problem. In practice several testers run on one server. The number of testers that one server can support is limited more by memory than CPU because each test run requires significant memory to track the TCP connection progress. Each tester can run multiple tests simultaneously, currently set in the low hundreds. Upon loading, each tester registers itself with the Test Distributor. This is done over TCP so if a tester unexpectedly goes offline it can be detected fairly quickly and removed from the Test Distributor pool. A tester that has gone offline is the typical cause for an intermittent port marked as "error" although after tuning the server sizes and tester counts this is now rare. The tester receives a test from the Test Distributor and puts it in a queue waiting for one of its hundreds of available testers in its pool to become free. When the tester becomes free it receives the test request and runs the test on the ip address and port combination specified. On a stealth port, three connection attempts are made over the course of 2 seconds. Once the state of the port has been determined (open, closed, stealth) the test result is sent back to the Test Distributor. Raw sockets are used to send a TCP SYN packet to the ip address being tested. This is deliberate. If Node.js's built in TCP methods were used and an open port is found a complete connection would be made. By using raw sockets we have control

bash: Test a TCP connection - pet2cattle

One of our customers is securing his network, and firewall changes were made that needed to be tested. In this case, the new servers were not yet deployed in that specific network. But… We did want to test the connections before deploying the servers 🙂 In this blog post, I will show you how to create listening ports on a machine to test the connection from another network using netcat on Linux or portqry on Windows.PreparationWindowsLinuxStarting a listenerChecking the portsLinuxUDPTCPWindowsUDPTCP The scriptPreparationIn this case, we are using netcat and portqry as our testing tools, depending on your operating system. Follow the procedure below to install it on your system.WindowsDownload portqry here (Direct link) and save PortQryV2.exe to a temporary location. Run it and extract the files somewhere on the system that you will use to test the ports. It can test both TCP and UDP.LinuxDepending on what Linux flavor you’re running, the installation could be different than the command line below in which I install it on a Ubuntu machine using apt getsudo apt install netcatStarting a listenerAfter running the command below in a PowerShell prompt from within the directory in which you saved the script, the New-Portlistener PowerShell function is available in your session (Alternatively, you could run it from PowerShell ISE). .\New-PortlistenerNow that the function is available, you can start a TCP listener on port 9001, for example by running this command:New-Portlistener -UDPPort 9001After running, you will see this output on your screen:You can press Escape to stop the listener, and it should show this as the output:Stopped listening on UDP port 9001If you are trying to start a listener which is already active, it will show an error (In this example, I used TCP port 3389 which is the default RDP port)WARNING: TCP Port 3389 is already listening, aborting...Note: Windows Firewall could give pop-ups when starting the listenerChecking the portsIf you have a TCP or UDP listener port running on a Windows machine, you can start testing the connection from a Windows or Linux machine in another network.LinuxUDPTo use netcat for checking a UDP connection, you can. Starting a TCP connection test. FortiTester tests TCP concurrent connection performance by generating a specified volume of two-way TCP traffic flow via specified ports. To start a TCP connection test: Go to Cases Performance Testing TCP Connection to display the test case summary page. TCP connection state: When testing TCP connections, Test-NetConnection returns the TcpTestSucceeded property, which is a Boolean value indicating whether the TCP connection

Test TCP connectivity with curl and Telnet

Concurrent clients, 1kB of HTTP payload returned, Keep-Alive turned on, 10 seconds (establishes exactly 1000 TCP connections that are serving HTTP requests).Test #2.1 (with TLS): Static 1kB content throughput test1000 concurrent clients, 1kB of HTTP payload returned, Keep-Alive turned on, 10 seconds (establishes exactly 1000 TCP connections that are serving HTTP requests).Only net/http, fasthttp and tcpserver have been benchmarked, as evio and gnet do not support TLS.Test #3: AES-128-CBC crypted 1kB content massive connections test1000 concurrent clients, 1kB of AES-128-CBC crypted HTTP payload returned, Keep-Alive turned off, 10 seconds (each HTTP request is a new connection).Test #4: AES-128-CBC crypted 1kB content throughput test1000 concurrent clients, 1kB of AES-128-CBC crypted HTTP payload returned, Keep-Alive turned on, 10 seconds (establishes exactly 1000 TCP connections that are serving HTTP requests).Test #5: Static 128 byte content throughput test with additional 1ms sleep1000 concurrent clients, 128 bytes of HTTP payload returned and 1 ms sleep, Keep-Alive turned on, 10 seconds (establishes exactly 1000 TCP connections that are serving HTTP requests).Test #6: Static 16kB content massive connections test1000 concurrent clients, 16kB of HTTP payload returned, Keep-Alive turned off, 10 seconds (each HTTP request is a new connection).Why?I always find it enlightening to know why someone did something. That's why this section is here.When I started writing a new high performance SOCKS5 and HTTP proxy server to replace danted in my setup, I realized that I needed some functionality that goes beyond the core listen-accept-handle logic like graceful restart/shutdown and strict error handling.I evaluated evio and later gnet but that reminded me of doing async IO in PHP a decade ago which might have been a necessity there but Go has it's own event loop and I was curious why one would re-implement all this in a client library and relinquish the way you write network code in Go (basically by using a goroutine per connection) – the answer is was speed.I started benchmarking the mentioned libraries against a naive go handle(...) approach and it soon turned out that spawning a new goroutine for each connection was simply too expensive.After creating a new goroutine worker pool (modeled after the one found in fasthttp) I was able to reach numbers (in reqs/sec) that were on par with these libraries.Now, after some rounds of optimization, tcpserver is faster in almost all benchmarks than any other library I've come across and you get zero-copy and TLS "for free" – simply by using Go's own net/* functionality!Licensetcpserver is available under the MIT license.