Macbook troubleshooting

Hello everyone, I'm new to the forum, and I'm having a problem that I hope someone can shed some light on.

As of recently my Macbook has at times just stop connecting to the internet. My line of work is logistics and customer support. I have a telephone that has to be connected to a modem, and from the phone, there's a cable that you hook up to the ethernet port.

Anyway, while working I have multiple windows, tabs, apps ect. And I just randomly stop getting internet. I know the internet is working because of the phone hooked-up to the modem is working perfectly, otherwise I wouldn't get a dial tone. And to get it functioning again, I have to restart my Macbook. I know is isn't the solution, but I haven't an idea as to why is would be happening.

Any help, tips or hints would greatly be appreciated.