I have a 4 month old dachshund mix n he is well behaved and was doing fine on leash but at random times he just stops flops down and will not budge. I have tried treats and encouragement as well as tried pulling him. But he acts like a rag doll. He walks fine with my other dogs but its hard to walk them at the same time all the time. Any tips would be very much helpful.

Maybe he just gets bored or tired. He's still young, maybe try shorter walks?

4 months is very young and shouldn't be going on too many walks, let alone allowed to be on the ground during those walks. So many disease can be on the ground that your puppy is still open to. So, I would advise, to stop taking puppy out for walks (maybe carry him) and work on the leash training itself at home.

Leash training is a whole lot more than just putting a leash on a dog and dragging it down the street. You need to teach your dog to respect you and to listen to you.

Would you take your toddler on a huge walk, making them walk the entire way? Or would you put the baby in a stroller?

Puppies are no different from human babies. They both tire quickly and frustrate quickly also. Making a 4 month old puppy go for walks every day is going to frustrate that puppy. Mentally, that pup is not ready for that.

To prep your pup (ha), practice leash training at home. Go in your back yard and do about a 15 min coarse of walking on a leash. 15 minutes will exhaust that pup. The older the pup gets, the longer you can go. Once the pup has all its necessary shots, you can start heading out. This type of prep work will help you out in the long run. The pup will learn to stay with you and that you're very interesting..

If you want to take your pup for a walk right now, carry him. Cherish the moment of this puppy being a baby. When he gets older (and heavier), he'll be able to walk on his own. I own large dogs.. so when they're babies, I hold them all the time. Rarely do I take my baby dogs out for walks with them walking on the ground.

That's what I advise anyway...