SSH tunneling is a technique to transfer arbitrary networking data using an encrypted SSH connection. It can be used to add encryption to not secure protocols such as HTTP and to bypassing firewalls. It is also named as port forwarding, there is a post related to C# implementation of SSH port forwarding. Here is presented… Read More »
If you have Java or .Net programming background you used to be familiar with exception which generated in runtime if something is going wrong with code execution. Linux C does not provide direct support to runtime error handling or exception handling. Usually code developer has to check return values from the functions. Generally C function… Read More »
What is sizeof? In C sizeof is not a function, it is the unary operator sizeof which is measured in the number of byte-sized storage units required for the type. Usually it is calculated during compilation but some compilers could create code which computes sizeof in runtime. Now small quiz related to sizeof. Possible that… Read More »
Got sick of multiple silly comments and decided to rid of them. Yesterday I added “Simple Google reCAPTCHA” plugin, so currently comment posting comment are protected by Google reCAPTCHA, Contact page is not secure yet. but I will implement some protection there also. I investigated with Wireshark how HTTP POST request of adding new comment… Read More »
The sysinfo system call returns a lot of useful system statistic data: memory usage, number of currently running processes, seconds since last boot. The only argument used by sysinfo is a pointer to a sysinfo structure. The first member of sysinfo structure is uptime which contains number of seconds since last reboot. For more details… Read More »
Query to DNS server and response that NNS client receives are not so user friendly as for SMTP or FTP. DNS query and response formats presented in RFC-1035. For example A type query to DNS sever to get IP addresses of cnn.com domain in byte-by-byte hex dump looks like: 000000 02 01 00 00 01… Read More »
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 »
In 1999 I implemented HTTP server for Windows NT with features of remote control and monitoring server machine. I gave the name Raposa to the server. The server code was written on VC++ 6.0 with MFC. Couple of days ago successfully I rebuilt the code on Visual Studio 2013. To my surprise all server services… Read More »
ifconfig is a system administration utility in Unix-like operating systems which presents network interface configuration, including IP addresses, masks, Mac addresses and a lot of other stuff. The ifconfig output may be slightly varying on different operating systems. The utility is very frequently included in shell scripts to get some network parameters. The presented below… Read More »