Category Archives: Testing

testing, debugging

ssl_error_protocol_version_alert in Wireshark or weak security protocol on the client side

I cannot connect to my site from my old Ubuntu 12.0 virtual machine. Instead of blog content the Firefox shows ssl_error_protocol_version_alert error. It means that browser does not support TLS protocol version that server requires. According to supports only TLS 1.2 and TLS 1.3 protocols. But Firefox browser users only SSL 3.0… Read More »

EOVERFLOW error on 32-bit Linux

EOVERFLOW (Value too large for defined data type) error or error with code 75 is defined in errno.h file. The error is very common on 32-bit Linux OS when code tries to proceed with size 2 GB or more. It is very simple to simulate the error. Let us create file with size which exceeds… Read More »

Processing Output Debug String Event

In previous article “Writing Windows Debugger in C#” the whole debugger architecture for Windows OS was discuss. This post describe how to process output debug string event sent by debugged process. On debugger side output debug string event is triggered by OutputDebugString function call, which has 2 versions: ASCII version OutputDebugStringA and Unicode version OutputDebugStringW.… Read More »

Writing Windows Debugger in C#

Actually C# is not the best language to call Windows Debugging functions. Several pinvokes and debugging structures definitions are required. They may be taken for winbase.h include file. In attached projects these pinvoke and structures definitions are located in PInvokes.cs file. Debugger is a program to debug another process. The debugger may start new process… Read More »

Analyzing application crash in CentOS Linux.

To diagnose program crashing failure let us create our own simple c++ application which will be crashing during execution. Save it as exemplo.cpp. Build executable without debug information: g++ -o exemplo exemplo.cpp When we start it we receive information that application crashed because of segmentation fault: ./exemplo Crashing application Segmentation fault (core dumped) The simplest… Read More »

Proxy server and its anonymity

I decided to test how proxy server anonymity looks like and how to control it. The purpose was to get HTTP request header which server receives from proxy when proxy settings are anonymous, semi-anonymous or what ever. I installed squid proxy server on one Linux machine and started to play with its settings located in… Read More »

How I tested my web hosting and got response time data graph

I decided to check how change my hosting response time during the whole day for this purpose I created simple bash script. The script is base on cUrl tool which sends GET request to some specific URL. If server is not responding 60 seconds timeout is used. The script requires 2 argument URL and… Read More »