From Console:
1
First Step
Login to your Wepwawet Control Panel
2
Second Step
Select your Server
3
Third Step
Make sure to Turn OFF the Server
4
Fourth Step
Under the General Section, Click the Files tab
5
Fifth Step
After that, Click on the server.properties file and go to the line that says allow-nether=true and change it to allow-nether=false and then click one Save Changes.
6
Sixth Step
After that, Head over to General tab, Click on Console and Start the server.
There you go! You have disabled the nether for your world!