He must serve one month of his sentence behind bars, and cannot appeal.
The 18-year-old has also been told he will be on probation and will have to undergo psychotherapy, as well as finishing college.
He was also convicted of assault and serious commercial fraud.
According to the prosecution the youth had been running a right-wing extremist forum on Skype, which he called "National Resistance and true National Socialists".
He shared numerous videos and audio files which portrayed National Socialism in a positive light.
In addition, together with a 20-year-old, he sprayed “Jews out” and a swastika on a glass pane of a local primary school.
He was also charged with using the chat forum for fraudulent purposes. He offered Nazi paraphernalia such as badges and coats of arms for sale, although he didn’t actually possess any such items. One person paid him €25.
The Prohibition Act of 1947 contains a number of provisions to combat the resurgence of National Socialist activities.