Category / Regulars

All posts which are not featured in the sliding header. This will be used to make sure featured posts are not shown twice on the home page.

by Nirupam Biswas

Securing the WordPress Login page

Of late I have seen quite a lot of brute force attempts to login into the admin account of this blog. The source IPs are wide and varied, ranging from Istanbul, Germany, Greece, US and more. In fact according to ArsTechnica article this has been happening for sometime now on a huge scale. I see a POST request on my site every few hours. Recently I submitted a list of such IPs to Deutsche Telekom Abuse Team for the offending IPs from their network.

Protection from the attack ArsTechnica suggested using

Limit Login and WP Better Security plugins. Limit Login is a simple and must have plugin. It blocks an IP for some hours our repeated failure attempts. Of course for this to be useful you need to have a strong password like mine, which is ….. . However, WP Better Security is the best but makes some drastic changes to your site. I don’t like to make so many changes, and would prefer that WordPress came bundled with those features. One of those features is modifying the login url. By default it is like http://blog.host/wp-login.php. This makes it an easy target. One simple way to fix this is change it.

Changing your login url

I do not want to physically rename wp-login.php, since that would mean after a WordPress upgrade the change would be gone. The other way is to rename it in your web-server configuration. Below is my relevant Nginx configuration. (If you are still using Apache then you may want to switch to Nginx.)

#!cink
server {
    server_name blog.host;
    # Other configs like root etc...
    location ^~ /wp-login.php {
        include phpparams.conf;
        if ($request_method = POST) { return 444; }
    }
    location ^~ /your-secret-login-page-name.php {
        rewrite ^ /wp-login.php break;
        include phpparams.conf;
    }
    # ...
}

The above config blocks all POST request to wp-login.php but allows GET requests. So, wp-login.php would show up but if someone tries to submit on that page then the server will close the connection (status 444 is a special code which instructs Nginx to close the remote connection). Since we are using ^~ to prevent Nginx from matching to any more regex locations so, if you have any location directive to match .php won’t be used. So, effectively your wp-login.php file source would be sent to the user instead of executing them. That is why I have included phpparams.conf. See the Nginx migration guide for the contents of phpparams.conf.

One Caveat

Now even if you open your-secret-login-page-name.php, the form will still send POST requests to wp-login.php, because after all that is the page which is being served. So, either you need to use web developer tools like Inspector to modify the web code or better write a GreaseMonkey or TamperMonkey script to do that for you.

by Nirupam Biswas

Process to get new LPG gas connection

There are no silver bullets but it is better to know the process to avoid harassment. I recently got Indane LPG gas after making rounds of their office for about a month. Most of these was due to the lack of info. SO, here you go.

First step is you need to get the KYC (Know Your Customer) form from the dealer. There is nothing special about it so, even if someone happens to have a soft copy of it then you can get it printed. I had to wait for 2 weeks to get this. One format of KYC document is available on Indane site (here), but the one I got from the dealer was a little different. They will also give you an affidavit form, which you need to get printed on a Rs 20 Stamp Paper and notarized by a lawyer. You can get that form from here.

Tip: If you live anywhere in Hitec City, Hyderabad then there is a small shop available in Madhapur to Stamp Papers and notarize documents. – http://maap.in/w

Fill the KYC form and affix a colored photograph. Along with the Stamp Paper and KYC you need to attach your address proof and photo Id proof. Also you should provide the Aadhaar number on the KYC form, though its photocopy need to be attached if you are providing another photo Id proof.

Some of the accepted address proofs are:-

  • Rental agreement
  • Credit / Bank statement
  • Electricity bill
  • Self-declaration attested by Gazetted officer
  • Flat allotment/possession letter

Some of the accepted photo Id proofs are:-

  • Passport
  • Aadhaar
  • Pan Card
  • Driving License

Once you submit all the above, they say, they will make a verification call in a week. After that you may go to your dealer and deposit a sum of Rs. 5000 to get the new connection.

However, in my case they did not call me. When I anyway went there after a week I got the connection. I had to dig through the applications dump to find mine. Rs. 5000 deposit includes price of gasket, regulator, one cylinder, a stove and other misc charges. Buying stove from them is purely optional, but the agency might try to force you to buy that.

Along with the above stuffs you get a connection certificate sort of paper and the gas booklet. According to the agency you can only apply for single cylinder when you are getting a new connection. You can get the second one after three months.

Hope the above info helps. May god help you with your Gas hunting. 😛

More info:-

by Nirupam Biswas

Configure your Belkin N150 router for BSNL broadband

  1. Login to your router dashboard. It should usually be at http://192.168.2.1.
  2. Now under “Inertnet WAN” click on “Connection Type”.
  3. Here select “PPPoE” and click on Next.
  4. Provide your BSNL username and password. Leave the “Service Name” field blank.
  5. For “VPI/VCI” field provide 0 and 35 as values.
  6. For “Encapsulation” field choose “LLC”.
  7. Leave all other fileds to their default values.
  8. Now Apply Changes. It will take around 30 seconds for the router to restart.
  9. Notice the top-right corner of the page and check the status. If it says “Connected”, then you are good to go.
  10. Else click on the “Home” link near that. On the home page click on Connect button.

Now you should be able to use this Wifi router with your BSNL broadband. Happy surfing. 🙂

PS: Now you no longer need to use your computer to dial the BSNL connection and login. Your router has your BSNL username and password, it will do the dialing and logging in.

by Nirupam Biswas

Calculate Root of Any Whole Number in Java

The following Java program can find any root of a whole number. The logic is simple. Start by guessing some number and check if that is the correct value. If that overshoots then subtract some from the guess number else add to it. We add or subtract some fixed constant. If that constant is too big then we divide that constant by 10 to get a finer number.

#!java
public class CubeRoot {

    public static void main(String[] args) {
        System.out.println(String.format("%.2f", cubeRoot(0, 2)));
        System.out.println(String.format("%.0f", cubeRoot(8, 0)));
        System.out.println(String.format("%.4f", cubeRoot(10, 4)));

        System.out.println(String.format("%.4f", root(10, 2, 4))); // Square Root
        System.out.println(String.format("%.4f", root(100, 5, 4))); // 5th Root
    }

    private static double cubeRoot(int n, int precision) {
        return root(n, 3, precision);
    }

    private static double root(int n, int root, int precision) {
        double x = n / 5.0; // 5 is better than 4 since this will have bigger
                            // step. 3 is very bad choice since there are some
                            // no.s which will never have rational output when
                            // divided by 3, e.g. 5.
        double powX;
        double d = 10;
        double lastX = 0;
        double lastLastX = 0;
        do {
            powX = Math.pow(x, root);
            if (matches(powX, n, precision))
                return x;
            else {
                if (matches(lastLastX, x, precision)) {
                    // If the lastLast x value is same as current then we are
                    // trapped in a loop, since the current d is not small
                    // enough. We need to now step at finer precisions.
                    d /= 10;
                    if (matches(d, 0, precision + 1)) {
                        return x;
                    }
                }
                lastLastX = lastX;
                lastX = x;
                if (n < powX) {
                    x -= d;
                } else {
                    x += d;
                }
                // System.out.println("(x=" + x + ", d=" + d + ")");
            }
        } while (true);
    }

    private static boolean matches(double a, double b, int precession) {
        return ((int) (a * (long) Math.pow(10, precession)))
                - ((int) (b * (long) Math.pow(10, precession))) == 0;
    }

}