I’ve some notes : Maxovy poznamky k smb.conf (it is in CZ, maybe i will translate it to ENG).
ad_win10: windows are using latest samba version and protocols, meanwhile TOS is using 3.6 version. TOS can loose election to “samba master” and win10 can win, in that case, shares won’t work.
ad_firewall: you should first check sharing option for your workgroup and assign it to some network you have (public,home,private…) and later allow samba ports just for that network
note: there are also “min/max protocol” options which manage what will be used. SMB1,SMB2,SMB3 (it is not related to samba version), where it is recommended to use SMB2 as max (so smb1 and 2 will be used). Samba 3.6 use SMB2(resp. SMB2_10), Samba4.x use SMB3(SMB3_11) which is default on win10. more info: https://accedian.com/enterprises/blog/troubleshooting-smb-performance/
note2: regarding the ports …each dialect uses different ports, and if you have min=smb1 and max=smb2 (or smb3) you never know what dialect is used by each client.
SMB1 >> UDP: 137,138 TCP:139,445
SMB2 >> UDP: TCP:445
ad_master: there are “master” + “os level” options in smb.conf where you can force TOS be domain/preffered/local master