Abstract : The Internet is an advancement of information technology is very instrumental in various fields today. The Internet connects everyone despite being far apart. So the internet is very important role in terms of communication. The Internet is widely applied in the education sector, government, and even companies. Through the internet, data exchange in these sectors can be done. However, the exchange of such data must be secure or accessible only to the person entitled to the data. For that network security is needed to protect data owned by each agency or sector. Researchers in this paper develop network security with firewall using MikroTik RB941. In this research, built a server using MikroTik RB941 with Firewall feature to restrict visitor access rights, where only recognizable visitors will be able to access the server. So the firewall here filters the user's access to the server. From the test results obtained that the firewall applied to MIkroTik RB941 can perform filtration process on the user who tries to access to the server. Kata Kunci : network security, firewall, mikrotik