I agree with advice above, he needs to realise that he isn't the Alpha male.
Another way to reinforce this is never let him go through a door or gate in front of you, make him sit, open and go through the door/gate, and then call him through.
He will learn his place in the pecking order.
If you have a other half, make sure that she also applies these rules.
This is a must ,no dog is tripping me up or coming in or out the house/ car before I say it can , basics
Also fill his bowl ,
Make him sit and stay ,
Tell him to " take it " when u say so ,and then take it away before he gets to it( move it to another area , make the beggar wait )
if he also moves an inch before the command , a sharp " No " then put the food away (or move food to another area) , and do the same 10 mins later,( make the beggar stay , exactly where you told it )
You pay for its food and shelter , you are the boss ,it will eat when you say so , not when it wants to
To be quite honest all the above replies to the post SHOULD be installed from day 1,
Sod having my own dogs being misbehaved or growling at me , a big NO NO
Your and your family are the boss ,
Be a bit mean( no violence, but grip the beggar if needed , your voice should make it feel like the wrath of God has dropped down on it, bollock the dog , good style, but only when it's being a dick lol) it will soon get the message
Just remember , it's a bleddy dog

good luck
Kjf