SSH keys are a way to identify computers, without using passwords. If you have used git, or if you are an active participant in the open-source community, you will be definitely familiar with the important role of SSH. In the case of remote servers, when using SSH logins, the server will ask for password each time you try to login. This could be avoided by adding public key to server's authorized_keys.
Technical Solution | 2 min read
This article explains a relatively new feature in php; The Built-in web server. Other languages like python and ruby already had their own simple HTTP servers where you can convert you local folders/directories into a simple HTTP server (for python: python -m SimpleHTTPServer) which serves scripts and HTML files and basically does almost everything apache does. Almost! To use this functionality in PHP, you need to have a version 5.4 or above. Using terminal, navigate to the root of the folder where the index.php or index.html and run the following command.
Many a times while developing sites we would need to post data to an external server, for example if you have an ecommerce site and wants to manage CRM in a different server at such time you would need to pass the order details to different server. We can POST the data using CURL or drupal_http_request().
If you are a Nginx web server user and using Drupal as your CMS, it is quite different for redirects. Imagine that you have two websites, so if we change from an old site to a new site some of the URL will return 'Page not found'. So for that reason we can redirect them to the correct URL. If you are also looking for a 301 redirect for your Drupal site please read on.
Recently we had faced a problem in a Drupal site after installing Memcached on a server with CentOS and having csf as firewall. Memcache is a process which is always running in memory and the server is configured to send automated mails regarding this process. So we need to exclude this process from csf. If you are facing the same problem in your Drupal site and want to know how to whitelist a process in csf, then read on to get the solution
Many Drupal users have encountered a "Client does not support authentication protocol requested by server; upgrading MySQL client." during the setup of a new install of Drupal. If you are facing this error while installing Drupal then continue reading to find the solution.
Technical Solution | 1 min read
APC or Alternative PHP Cache (APC) is a free and open opcode cache for PHP. APC allows for caching of opcode generated during PHP script parsing and execution by the Zend engine. If you are using APC 3.1.9 and you are using the default configuration you might run into the error where most PHP requests will return a warning message "PHP Warning: Unknown: Unable to allocate memory for pool. in Unknown on line 0"
Drupal Performance Tips: Prevent spam bots from posting to your Drupal site and prevent server loads due to repeated posts
One of the Drupal sites we maintain had recently started slowing down considerably in spite of the site mostly being static and in spite of boost set up on the server. On examination of the site we found that two things were happening on the site. One was that the site was being crawled indiscriminately by rogue crawlers. This we solved using the DDOS deflate script and setting DDOS deflate to run every 10 seconds. The second problem was that there were some bots which were continuously sending POST requests to /comment/cid/reply pages. For this we had to come up with a workaround.
Simple solution to protect your Drupal website/VPS/webserver from DDOS by crawler bots that cause apache load spikes
If you run a reasonably popular site there is a very good chance that you will get crawled by unscrupulous crawlers once in a while. The regular search crawlers from the popular search engines like the Google bot, Yahoo bot, Bing bot themselves are pretty intensive when they crawl sites but they do have limits on the number of pages crawled per visit and the number of simultaneous connections opened to your server. However there are lots of unscrupulous crawlers like spam bots, email harvesting bots and even some search engines who do not set any reasonable limits on the number of simultaneous connections to your server. There are hardware solutions that are available to prevent this but they may not be affordable for everybody. There is however a simple netstat based solution to prevent DDOS.