CMD Find Network Usage - shell

My work computer is using an insane amount of data every month. It is driving my ISP costs through the roof.
Is there a way in command line to list all the "Devices/Objects" on the network to see what is using all my data?

You can monitor your network traffic using: netstat -e
Please read this article :
https://www.petri.com/netstat-command-monitor-network-traffic
Also why don't you try to use Resource Monitor- it is available in all windows Machines.
It will tell you how much data is used by what app.

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10k Concurrent connections with jmeter

I have a 32GB, i7 core processor running on windows 10 and I am trying to generate 10kVU concurrent load via jmeter. For some reason I am unable to go beyond 1k concurrent and I start getting BindException error or Socket connection error. Can someone help me with the settings to achieve that kind of load? Also if someone is up for freelancing I am happy to consider that as well. Any help would be great as I am nearing production and am unable to load test this use case. If you guys have any other tools that I can use effectively, that would also help.
You reach the limit of 1 computer, thus you must execute in distributed environment of multiple computers.
You can setup JMeter's distributed testing on your own environment or use blazemeter or other cloud based load testing tool
we can use BlazeMeter, which provides us with an easy way to handle our load tests. All we need to do is to upload our JMX file to BlazeMeter. We can also upload a consolidated CSV file with all the necessary data and BlazeMeter will take care of splitting it, depending on the amount of engines we have set.
On BlazeMeter we can set the amount of users or the combination of engines (slave systems) and threads that we want to apply to our tests. We can also configure additional values like multi locations.
1k concurrent sounds low enough that it's something else ... it's also the default amount of open file descriptor limits on a lot of Linux distributions so maybe try to raise the limit.
ulimit -Sn
will show you your current limit and
ulimit -Hn
will show you the hard limit you can go before you have to touch configuration files. Editing /etc/security/limits.conf as root and setting something like
yourusername soft nofile 50000
yourusername hard nofile 50000
yourusername - will have to be the username of the user which with you run jmeter.
After this you will probably have to restart in order for the changes to take effect. If not on Linux I don't know how to actually do this you will have to google :D
Recommendation:
As a k6 developer I can propose it as an alternative tool, but running 10k VUs on a single machine will be hard with it as well. Every VU will take some memory - like at least 1-3mb and this will go up the larger your script is. But with 32gb you could still run upto 1-2kVUs and use http.batch to make concurrent requests which might simulate the 10k VUs depending on what your actual workflow is like.
I managed to run the stages sample with 300VUs on a single 3770 i7 CPU and 4gb of ram in a virtual machine and got 6.5k+ rps to another virtual machine on a neighboring physical machine (the latency is very low) so maybe 1.5-2kVUs with a a somewhat more interesting script and some higher latency as this will give time to the golang to actually run GC while waiting for tcp packets. I highly recommend using discardResponseBodies if you don't need them and even if you need some to actually get the response for them. This helps a lot with the memory consumption a each VU

How to calculate total network traffic for a period of time for a specific application?

I'm doing performance testing of a native application on Windows and I need to calculate how much more internet traffic new application version produce compared to previous version. Because application is meant to be working in environment with limited internet connection.
Fiddler displays only HTTP and FTP requests and only those that were sent through proxy. In theory application can ignore proxy and use other protocols or sockets.
Resource Monitor seems to contains only average network activity for last minute (Total B/sec). It is not enough for me because network traffic produced by application is not constant.
Network-related performance counters doesn't contain no relevant counters to look at.
TCPView for some reason do not show information for some processes. It display traffic for specific connection rather than application and when connection is closed information is lost.
After more detailed research I found that Sysinternals Process Explorer looks like appropriate tool for internet traffic estimation. You can add Network Send Bytes and Network Recieve Bytes columns to processes table and manually calculate their values difference at the time range boundaries that you are interested in. In order to this to work you need to start Process Explorer as administrator.

How to check the maximum bandwidth available for my network, without using any tool?

I am trying to get the maximum bandwidth available on eth0. I can check the currrent speed of the network by going to /sys/class/net/eth0/statistics/rx_bytes. Let say I am getting speed of 20Mbps. How to get if what total bandwidth available on this network? I am writing a shell script. I donot want to use any tool for this purpose!
You can try using something like wget and see if you can capture and process the resultant output.
something like this
check internet speed using terminal

How to capture network traffic by process name in mac?

I am trying to automate the process of capturing network packets send by a particular application.I don't have problem in windows as I am using Microsoft Network Monitoring tool and that gives all the traffic send based on the process.Now the problem is that we need to achieve the same result in mac as well.
We used Wire-shark in mac for capturing network traffic after a long research but still wireshark does not capture by process name.We tried some tools that captures based on process name but with very limited information. We need the full packet informations to be captured.
What will be the best way to achieve the result in mac as like we are getting in windows?
what all parameters can be used to filter the wanted data...?
I am in fact trying to get the port number used by the process but is that a right approach ? I am not sure we can zero down based on port number.
Any help would be greatly appreciated...
Thanks in advance...
You can use lsof command, but it's more complex than netstat.
Here is a guide: lsof survival guide

Simulating Slow Internet Connection [closed]

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I know this is kind of an odd question. Since I usually develop applications based on the "assumption" that all users have a slow internet connection. But, does anybody think that there is a way to programmatically simulate a slow internet connection, so I can "see" how an application performs under various "connection speeds"?
I'm not worried about which language is used. And I'm not looking for code samples or anything, just interested in the logic behind it.
Starting with Chrome 38 you can do this without any plugins. Just click inspect element (or F12 hotkey), then click on "toggle device mod" and you will see something like this:
Among many other features it allows you to simulate specific internet connection (3G, GPRS)
P.S. for people who try to limit the upload speed. Sadly at the current time it is not possible.
P.S.2 now you do not need to toggle anything. Throttling panel is available right from the network panel.
Note that while clicking on the No throttling you can create your custom throttling options.
If you're running windows, fiddler is a great tool. It has a setting to simulate modem speed, and for someone who wants more control has a plugin to add latency to each request.
I prefer using a tool like this to putting latency code in my application as it is a much more realistic simulation, as well as not making me design or code the actual bits. The best code is code I don't have to write.
ADDED: This article at Pavel Donchev's blog on Software Technologies shows how to create custom simulated speeds: Limiting your Internet connection speed with Fiddler.
Google recommends:
Network Link Conditioner on OSX
Clumsy on Windows
Dummynet on Linux
On Linux machines u can use wondershaper
apt-get install wondershaper
$ sudo wondershaper {interface} {down} {up}
the {down} and {up} are bandwidth in kpbs
So for example if you want to limit the bandwidth of interface eth1 to 256kbps uplink and 128kbps downlink,
$ sudo wondershaper eth1 256 128
To clear the limit,
$ sudo wondershaper clear eth1
I was using http://www.netlimiter.com/ and it works very well. Not only limit speed for single processes but also shows actual transfer rates.
There are TCP proxies out there, like iprelay and Sloppy, that do bandwidth shaping to simulate slow connections. You can also do bandwidth shaping and simulate packet loss using IP filtering tools like ipfw and iptables.
You can try Dummynet, it can simulates queue and bandwidth limitations, delays, packet losses, and multipath effects
Use a web debugging proxy with throttling features, like Charles or Fiddler.
You'll find them useful web development in general. The major difference is that Charles is shareware, whereas Fiddler is free.
Also, for simulating a slow connection on some *nixes, you can try using ipfw. More information is provided by Ben Newman's answer on this Quora question
You can use NetEm (Network Emulation) as a proxy server to emulate many network characteristics (speed, delay, packet loss, etc.). It controls the networking using iproute2 package and it's enabled in the kernel of most Linux distributions.
It is controlled by the tc command-line application (from the iproute2 package), but there are also some web interface GUIs for NetEm, for example PHPnetemGUI2.
The advantage is that, as I wrote, it can emulate not only different network speeds but also, for example, the packet loss, duplication and/or corruption, random or defined delay, etc., so apart from the slow connections, you can also emulate various poorly performing networks and transmission errors.
For your application it's absolutely transparent, you can configure the operating system to use the NetEm as a proxy server, so all connections from that machine will be routed through it. Or you can configure only a specific application to use that proxy.
I have been using it to test the performance of an Android app on various emulated poor-performance networks.
Use a tool like TCPMon. It can fake a slow connection.
Basically, you request it the exact same thing and it just forwards the exact same request to the real server, and then delays the response with only the set amount of bytes.
For Linux, the following list of papers might be useful:
A Comparative Study of Network Link Emulators (2009)
KauNet: A Versatile and Flexible Emulation System (2009)
Dummynet Revisited (2010)
Measuring Accuracy and Performance of Network Emulators (2015)
Personally, whilst Dummynet is good, I find NetEm to be the most versatile for my use-cases; I'm usually interested in the effect of delays, rather than bandwidth (i.e. WiFi connection issues), and it's super-easy to emulate random packet loss/corruption, etc. It's also very accessible, and free (unlike the hardware-based Linktropy).
On a side-note, for Windows, Clumsy is awesome. I would also like to add that (regarding websites) browser throttling is not an accurate method for emulating real-life network issues (I think "TKK" commented on a few of the reasons why above).
Hope this helps someone!
One common case of shaping a single TCP connection can actually be assembled from dual pairs of socat and cpipe in UNIX fashion like this:
socat TCP-LISTEN:5555,reuseaddr,reuseport,fork SYSTEM:'cpipe -ngr -b 1 -s 10 | socat - "TCP:localhost:5000" | cpipe -ngr -b 1 -s 300'
This simulates a connection with bandwidth of approximately 300kB/s from your service at :5000 and to at approximately 10kB/s and listens on :5555 for incoming connections. Caveat: Note that this per-connection, so each individual TCP connection gets this amount.
Explanation:
The outer (left) socat listens with the given options on :5555 as a forking server. The first cpipe command in the SYSTEM:... option then throttles data that went into socket :5555 (and comes out of the first, outer socat) to at most 10kByte/s. That data is then forwarding using another socat which connects to localhost:5000 (where the service you want to slow down should be listening). Data from localhost:5000 is then put into the right cpipe command, which (with the given values) throttles it to about 300kB/s.
The option -ngr to cpipe is important. It causes cpipe to read non-greedily from its input file-descriptor. Otherwise, you might get stuck with data in the buffers not being forwarded and waiting for a reply.
Using the more common buffer tool instead of cpipe is likely possible as well.
(Credits: This is based on the "double-tee" recipe by Christophe Loor from the socat documentation)
Mac OSX since 10.10 has an app called Murus Firewall, which acts as a GUI to pf, the replacement for ipfw.
It works very well for system-wide or domain-specific throttling. I was just able to use it to slide my download speed between 300Kbps and 30Mbps to test how a streaming video player adjusts.
Updating this (9 years after it was asked) as the answer I was looking for wasn't mentioned:
Firefox also has presets for throttling connection speeds. Find them in the Network Monitor tab of the developer tools. Default is 'No throttling'.
Slowest is GPRS (Download speed: 50 Kbps, Upload speed: 20 Kbps, Minimum latency (ms): 500), ranging through 'good' and 'regular' 2G, 3G and 4G to DSL and WiFi (Download speed: 30Mbps, Upload speed: 15Mbps, Minimum latency (ms): 2).
More in the Dev Tools docs.
There is also another tool called WIPFW - http://wipfw.sourceforge.net/
It's a bit old school, but you can use it to simulate a slower connection. It's Windows based, and the tool allows the administrator to monitor how much traffic the router is getting from a certain machine, or how much WWW traffic it is forwarding, for example.
There is a simple and practical way to do it, without any application or code. Just connect to the internet using a mobile hotspot. Keep moving the hotspot (phone) away from the connected device to simulate slower networks. 😉

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