Block .exe .mp3 .flv .pdf .mp4 or many more using Mikrotik Router

Login Via WinBox>

Goto >> New Terminal 

1. Enable Web Proxy

We enable this web proxy without cache on disk.

Type:  

ip proxy set enabled=yes port=8080 cache-on-disk=no

2. Add proxy access rules

Goto web Proxy > add > select path> *.exe > action > deny > apply > ok

or 

Goto web Proxy > add > select path> *.mp3 > action > deny > apply > ok

or

Goto web Proxy > add > select path> *.flv > action > deny > apply > ok

or

Goto web Proxy > add > select path> *.pdf > action > deny > apply > ok

or

Goto web Proxy > add > select path> *.mp4 > action > deny > apply > ok

Have Fun!!