I have a ubuntu server machine which wasn't accessible with its hostname in our LAN by other windows pcs. Since we don't have a DNS server (we use our router for that) I had to install the samba service (which AFAIK includes netbios).
Now the DNS is working properly and other pcs in the internal LAN can access it via its DNS name.
My question is: I didn't share anything (no folders or anything else) via samba, but do I have to disable something in order to make my server secure? This is an authentication server and I'd like it to be accessible by other pcs in the LAN but secure enough if it connects to the internet (outside our LAN).