Using headphones in front panel

I was troubleshooting someone's desktop computer which they have realtek internet desktop speakers in. When they use the headphones they do have sound but there is also sound coming out of the desktop. They didn't want any sound coming out of the desktop. I played around with all the settings I could with Realtek settings and audio settings within the control panel. I also did a run as and logged on as admin but could not get the sound to not come out of the desktop. Only solution I found was to use the back panel which worked. Can this be done plugging the headphones into the front panel?

 

I meant internal desktop speakers not internet speakers haha. Thanks.