Monitor open ports using PHP (snippet)

How can you really know if a port is open or closed? Most of the scripts around the web fail doing it’s job, not because they are wrong but because they are not doing their job as they should.

Am I on drugs? No, not now 😉 basicly, what all scripts do is:

That will tell you if yourhost is open on that port but sometimes it will just hang there, why? there are many reasons why a server or service could hang (I’m not covering that part … at least not for free :P), but the only thing you really need to know is, IT HAPPENS… when? how? why? it will.

So, if you are in the middle of coding some script that let’s you monitor your servers / services without worrying about that “small particular issue”, you are in the right place, check out the code:

That’s a mess! Yes I know, it is dirty and uggly but it works. That function takes 4 arguments, $ip (server’s IP), $port (server’s port), $request and $replies (you can use comma delimited here in case you need to receive one or more answers).

How it works? Well copy that piece of code to any php file and call it this way:

Remember, all requests and replies depends on the server’s side, be aware of that 😉

mod_security 2 for Ensim X CentOs 4.6

ModSecurity is a great application which will help you to prevent attacks (including injections) to your webserver. On this article I’ll cover the installation of ModSecurity 2.5.1 on CentOS 4.6 with Apache2 running Ensim X.

First you need to meet the requirements:

  • libxml2
  • libxml2-devel
  • httpd-devel
  • apr-devel
  • apr-util-devel
  • pcre-devel

You can use yum in order to install/upgrade the mentioned packages.

Once you met the requirements you can go and download mod_security from here.

By now mod_security should be installed on your system and we are just 1 step away from glory. You need to modify your apache config’s file /etc/httpd/conf/httpd.conf (backup your config first!!!).

Edit your /etc/httpd/conf/httpd.conf file and locate the LoadModule’s section (DSO) and at the following lines:

We are almost done, we have mod_security installed and Apache configured to load mod_security. If you noticed, the last line we added (Include conf/modsecurity/*.conf) makes reference to the default rules mod_security includes in another file modsecurity-core-rules_2.5-1.6.0.tar.gz

If you didn’t get any error/warning check your logs just to make sure apache restarted without issues. If no errors then that means you’ve succesfully installed mod_security on your server hurray! 🙂

Take note that mod_security 2 has it’s default rules which are completely different than mod_security 1, you are free to go to /etc/httpd/conf/modsecurity and change/add rules according to your needs, and I highly recommend you to read ModSecurity documentation before doing that.

I took the best of the following sites to bring you this small HOWTO:

http://www.eth0.us/mod_security
http://carrero.es/instalar-modsecurity-2-en-plesk/1374

That’s all for today, I’m outta here 😉