Archive for the ‘TCP’ Category
Posted by jpluimers on 2018/11/08
Based on:
- Download the most recent x64 Apache binaries for Windows from [WayBack] Apache VC15 binaries and modules download (at the time of writing: https://www.apachelounge.com/download/VC15/binaries/httpd-2.4.34-win64-VC15.zip )
- Extract recursively to
D:\bin
- Run the UltrawareController locally
- Run
D:\bin\httpd-2.4.34-win64-VC15\Apache24\bin\ab.exe -n 1000 -c 10 http://localhost:8000/foo
This will run the ab Apache benchmark tool with 1000 connections using 10 threads all doing the same http GET request at http://localhost:8000/foo
If you want to test TLS (https) connections, then you need to use the abs tool in the same directory as the ab tool supports http-only (when you still try, you get the message SSL not compiled in; no https support as explained in [WayBack] Add https support to Apache Bench on Windows – Stack Overflow).
Download location via [WayBack] windows – Is there any link to download ab Apache benchmark – Stack Overflow:
There are many more command-line parameters documented at [WayBack] ab – Apache HTTP server benchmarking tool – Apache HTTP Server Version 2.4, this is the summary:
Synopsis
ab [ -A auth-username:password ] [ -b windowsize ] [ -B local-address ] [ -c concurrency ] [ -Ccookie-name=value ] [ -d ] [ -e csv-file ] [ -f protocol ] [ -g gnuplot-file ] [ -h ] [ -Hcustom-header ] [ -i ] [ -k ] [ -l ] [ -m HTTP-method ] [ -n requests ] [ -p POST-file ] [ -Pproxy-auth-username:password ] [ -q ] [ -r ] [ -s timeout ] [ -S ] [ -t timelimit ] [ -Tcontent-type ] [ -u PUT-file ] [ -v verbosity] [ -V ] [ -w ] [ -x <table>-attributes ] [ -Xproxy[:port] ] [ -y <tr>-attributes ] [ -z <td>-attributes ] [ -Z ciphersuite ] [http[s]://]hostname[:port]/path
Via: [WayBack] apache – ab load testing – Stack Overflow
––jeroen
Posted in Communications Development, Development, HTML, HTTP, Internet protocol suite, Software Development, Web Development | Leave a Comment »
Posted by jpluimers on 2018/11/07
Posted in *nix, Awk, bash, Communications Development, Development, Internet protocol suite, Power User, Scripting, Software Development, SSH, TCP | Leave a Comment »
Posted by jpluimers on 2018/10/09
Netcat to the rescue waiting for a Windows 10 upgrade to finish (which can take hours):
while ! nc -z 172.22.0.67 3389; do echo "sleeping"; sleep 10; done; echo 'The server is up!'
Via: [WayBack] tcp – How can I trigger a script when a certain port becomes available for requests? – Unix & Linux Stack Exchange, quoting from the answer:
nc is Netcat, “the Swiss-army knife for TCP/IP”,-z means: do not send any data, just check if the port is open,while ! nc -z …; do sleep 0.1; done: keep checking and sleeping for one tenth of a second until the port opens up, i.e. Netcat returns with a zero (success) status.
–jeroen
Posted in *nix, *nix-tools, Communications Development, Development, Internet protocol suite, Power User, TCP, Windows | Leave a Comment »
Posted by jpluimers on 2018/08/01
Despite many posts saying you can use it on other than outbound connections, lets quote that it doesn’t:
MaxUserPort controls “outbound” TCP connections
[WayBack] MaxUserPort is used to limit the number of dynamic ports available to TCP/IP applications.
…
It’s never going to be an issue affecting inbound connections.
MaxUserPort is not the right answer if you think you have an inbound connection problem.
Source: [WayBack] MaxUserPort – what it is, what it does, when it’s important – Blog du Tristank
The side of the TCP connection that closes is gets the TIME_WAIT state, which means you should avoid your server to terminate connections because it then will run out of available ports. Clients should disconnect when done (or when done for the foreseeable future) otherwise the server gets the 2MSL TIME_WAIT penalty as for instance explained by [WayBack] TIME_WAIT and its design implications for protocols and scalable client server systems – AsynchronousEvents.
The solution for inbound connections is that your TCP based protocol should enforce either the client to close the connection, or to use some form of client pooling so there is no need for many connection setup/teardowns of short lived connections.
TIME_WAIT can last for about ~10 minutes if you are unlucky.
More recommended reading:
–jeroen
Posted in Communications Development, Development, Internet protocol suite, Software Development, TCP | Leave a Comment »
Posted by jpluimers on 2018/03/07
It was fitting to bump into [WayBack] Packet Sender is a good tool when debugging protocols…” Written by Dan Nagle… – Lars Fosdal – Google+ on the day presenting [WayBack] Conferences/Network-Protocol-Security.rst at master · jpluimers/Conferences · GitHub
It also means that libssh2-delphi is getting a bit more love soon and will move to github as well after a conversion from mercurial.
Some of the things I learned or got confirmed teaching the session (I love learning by teaching):
Here is some more info:
–jeroen
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Posted in Communications Development, Delphi, Development, Encryption, Hardware, Harman Kardon, Home Audio/Video, HTTP, https, HTTPS/TLS security, Internet protocol suite, Let's Encrypt (letsencrypt/certbot), OpenSSL, Power User, Security, Software Development, TCP, TLS | Leave a Comment »
Posted by jpluimers on 2018/01/20
Before upgrading Tumbleweed this week, you need to review your openssh config.
This is not mentioned in Review of the week 2018/03 – Dominique a.k.a. DimStar (Dim*), but very important.
So be sure to read these before upgrading:
If you forget to review /etc/ssh/sshd_config, you get this in journalctl if you have specified your own MACs for instance when hardening according to [WayBack including rimemd160] Secure Secure Shell:
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Posted in *nix, *nix-tools, Communications Development, Development, Internet protocol suite, Power User, SSH, TCP | Leave a Comment »
In this article, we will explain you how to restrict a SSH user access to a specific directory using chrooted jail in Linux systems.
The Wiert Corner - irregular stream of stuff 