What ports do I have to open for SMB sharing?

So I have a relatively simple Setup for a 5-people Company I am currently working on. This Setup includes:

• 1 Server
• 1 Router
• 3+ "Clients"

I want to open a Windows Network share on the Server, to be accessed by the Clients. The SMB protocol that I configured uses Port 445 at some Point.

Unfortunately the consumer electronics Router I work with blocks port 445 and 139 for security considerations (netbios attacks), without any option to disable the blocking.

I called the router vendor's support and the plan now is to manually open some ports for forwarding the traffic necessary for SMB correctly.

Now I tried to Forward incoming port 445 connections to the local network, but unfortunately the connection is still dead.

What ports do I need to open for the connection to the Network share to work correctly?

SMB Ports [File Sharing]

• Protocol: tcp/udp
• Ports:
  137: netbios-ns
  138: netbios-dgm
  139: netbios-ssn
  445: smb-ds