Do you need same forge mod on server AND client?

[Do you need same forge mod on server AND client?]

Thankyou! It is so nice to have a definate answer. I was getting physically tired from juggling a bunch of Maybes and half-understood web guides in my brain!

 

[Do you need same forge mod on server AND client?]

Update: Checked by installing same mod client side.

Then everything works, but this is not what I had been hoping for.

[Do you need same forge mod on server AND client?]

Hello!

This if my first post here. I got interested in Forge because of its ability to add new blocks to the game.

However, I was under the impression that making a server-side mod would be sufficient for this.

After struggling through some tutorials, I finally managed to make a mod and got it to run on my server, only to have my client rejected with

 

Network Disconnect: Mod rejections [FMLMod:tutorial{1.0.0}]

 

So, do I need all my clients to have the same mods installed?, or could this be caused by some other error e.g. in my build.gradle file?