@Snehil Check these settings and modify if they are different, then test the speed (preferably from a laptop): Wireless: (for both wireless bands) System Parameters: Follow this guide and post a...

@grahame Refer to this thread. I suspect a similar situation.

I've meant, that your problem has been resolved by the engineers, changing your router's DNS settings.

Very well, if that was the issue then you have had a problem with your ISP provided DNS servers which is already resolved.

You can either turn off the DoS protection or to increase the DoS thresholds (eliminating the false positives) which are located in Advanced=>System Tools=>System Parameters, scroll to the bottom of...

@rchallapalli Probably you are trying to upgrade with a FW that is not for your region. On the bottom of teh device there should be a sticker where it is written what type of FW you have. Follow this...