Adventures & experiences in contemporary technology
There is a simple principal with the 7G Firewall from Perishable press: it is a set of mod_rewrite rules for the Apache web server that can be added to a .htaccess file and there also is a version for the Nginx web server as well. These check query strings, request Uniform Resource Identifiers (URI’s), user agents, remote hosts, HTTP referrers and request methods for any anomalies and blocks those that appear dubious.
Unfortunately, I found that the rules heavily slowed down a website with which I tried them so I am going have to wait until that is moved to a faster system before I really can give them a go. This can be a problem with security tools as I also found with adding a modsec jail to a Fail2Ban instance. As it happens, both sets of observations were made using the GTmetrix tool so it seems that there is a trade off between security and speed that needs to be assessed before adding anything to block unwanted web visitors.
There are times when blogs cease to exist and the only place to find the content is on the Wayback Machine. Even then, it is in danger of being lost completely. One such example is the subject of this post.
Though this website makes use of the facilities of Cloudflare for various functions that include the blocking of image hotlinking, the same outcome can be achieved using .htaccess files on Apache web servers. It may work on Nginx to a point too but there are other configuration files that ought to be updated instead of using a .htaccess when some frown upon the approach. In any case, the lines that need adding to .htaccess are listed below though the web address needs to include your own domain in place of the dummy example provided:
RewriteEngine on
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://(www\.)?yourdomain.com(/)?.*$ [NC]
RewriteRule .*\.(gif|jpe?g|png|bmp)$ [F,NC]
The first line turns on the mod_rewrite engine and you may have that done anyway. Of course, the module needs enabling in your Apache configuration for this to work and you have to be allowed to perform the required action as well. This means changing the Apache configuration files. The next pair of lines look at the HTTP referer strings and the third one only allows images to be served from your own web domain and not others. To add more, you need to copy the third line and change the web address accordingly. Any new lines need to precede the last line that defines the file extensions that are to be blocked to other web addresses.
RewriteEngine on
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://(www\.)?yourdomain.com(/)?.*$ [NC]
RewriteRule \.(gif|jpe?g|png|bmp)$ /images/image.gif [L,NC]
Another variant of the previous code involves changing the last line to display a default image showing others what is happening. That may not reduce the bandwidth usage as much as complete blocking but it may be useful for telling others what is happening.
The default PHP version on my outdoors, travel and photography website is 5.2.17 and that is getting on a bit now since it is no longer supported by the PHP project and has not been thus since 2011. One obvious impact was Piwik, which I used for web analytics and needs at least 5.3.2. WordPress 4.0 even needs 5.2.24 so that upgrade became implausible so I contacted Webfusion’s support team and they showed me how to get to at least 5.3.3 and even as far as 5.5.9. The trick is the addition of a line of code to the .htaccess file (near the top was my choice) like one of the following:
PHP 5.3.x
AddHandler application/x-httpd-php53 .php
PHP 5.5.x
AddHandler application/x-httpd-php55 .php
When I got one of these in place, things started to look promising but for a locked database due to my not watching how big it had got. Replacing it with two additional databases addressed the problem of losing write access though there was a little upheaval caused by this. Using PHP 5.5.9 meant that I spotted messages regarding the deprecation of the mysql_connect function so that needed fixing too (prefixing it with @ might be a temporary fix but a more permanent one always is better so that is what I did in the form of piggybacking off what WordPress uses; MySQLi and PDO_MySQL are other options). Sorting the database issue meant that I saw the upgrade message for WordPress as well as a mix of plugins and themes so all looked better and I need worry less about losing security updates. Also, I am up to the latest version of Piwik too and that’s an even better way to be.
For quite a while now, I have offline web servers for doing a spot of tweaking and tinkering away from the gaze of web users that visit what I have on there. Therefore, one of the tests that I apply to any prospective main Linux distro is the ability to set up a web server on there. This is more straightforward for some than for others. For Ubuntu and Linux Mint, it is a matter of installing the required software and doing a small bit of configuration. My experience with Sabayon is that it needs a little more effort than this and I am sharing it here for the installation of MySQL.
The first step is too install the software using the commands that you find below. The first pops the software onto the system while second completes the set up. The --basedir option is need with the latter because it won’t find things without it. It specifies the base location on the system and it’s /usr in my case.
sudo equo install dev-db/mysql
sudo /usr/bin/mysql_install_db --basedir=/usr
With the above complete, it’s time to start the database server and set the password for the root user. That’s what the two following commands achieve. Once your root password is set, you can go about creating databases and adding other users using the MySQL command line
sudo /etc/init.d/mysql start
mysqladmin -u root password ‘password’
The last step is to set the database server to start every time you start your Sabayon system. The first command adds an entry for MySQL to the default run level so that this happens. The purpose of the second command is check that this happened before restarting your computer to discover if it really happens. This procedure also is needed for having an Apache web server behave in the same way so the commands are worth having and even may have a use for other services on your system. ProFTP is another that comes to mind, for instance.
sudo rc-update add mysql default
sudo rc-update show | grep mysql