SSH Securing and Keygen ..

SSH Securing

What is SSH.. ?

  • Secure Shell or SSH is a network protocol that allows data to be exchanged using a secure channel between two networked devices. Used primarily on Linux and Unix based systems to access shell accounts,
  • SSH was designed as a replacement for Telnet and other insecure remote shells, which send information, notably passwords, in plaintext, leaving them open for interception. The encryption used by SSH provides confidentiality and integrity of data over an insecure network, such as the Internet.
  • SSH uses public-key cryptography to authenticate the remote computer and allow the remote computer to authenticate the user, if necessary.
  • SSH is typically used to log into a remote machine and execute commands, but it also supports tunneling, forwarding TCP ports and X11 connections; it can transfer files using the associated SFTP or SCP protocols.
  • SSH uses the client-server model.

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MySQL Tweaking

MySQL Tweaking

Login to the server and check out your my.cnf file.. To check whether your server is using the correct resourses perform the below commands and checks !!

Access the mysql prompt,

mysql> show status like %Open%_tables;
mysql> show variables like table_cache;

Run the above two commands and check Open_tables and Opened_tables If Opened_tables is big, then your table_cache variable is probably too small. So increase the table_cache variable. Open /etc/my.cnf and change/add table_cache=newvalue.

Run the following commands to check key_buffer_size, key_read_requests and key_reads

mysql> show variables like %key_buffer_size%;
mysql> show status like %key_read%;

If key_reads / key_read_requests is < 0.01, key_buffer_size is enough. Otherwise key_buffer_size should be increased.

mysql> show status like %key_write%;

command to check key_write_requests and key_writes, If key_writes / key_write_requests is not less than 1 (near 0.5 seems to be fine), increase key_buffer_size.

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SMARTD, a brief intro …

S.M.A.R.T.D

Whats it?

  • Smartd stands for SMART Disk Monitoring Daemon.
  • smartd is a daemon that monitors the Self-Monitoring, Analysis and Reporting Technology (SMART) system built into many ATA-3 and later ATA, IDE and SCSI-3 hard drives.
  • SMART is a monitoring system for computer hard disks to detect and report on various indicators of reliability, in the hope of anticipating failures.

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Squid

Web Proxies

Proxies: Introduction

A proxy is an intermediary application that sits between clients and servers.

Typically used to Control access, record activities and convert between protocols. Proxies exist for many different protocols SMTP/email DNS HTTP/Web IRC/IM/Chat.

Proxies: Web Objects

With a web proxy, we have the opportunity to cache and reuse certain server responses. When caching; we usually talk about objects.

For example: An HTML page A JPEG image A PDF document Flash animation.

Objects are identified by URL (Uniform Resource Locator).Note that sometimes the term web page refers to a number of different objects (HTML, images, etc).

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