15.0 smb.conf

[root]

After many hours of experimentation this works:
[global]
guest account = smbguest
netbios name = aa
security = user
null passwords = yes
map to guest = Bad Password
guest account = smbguest
# socket options = TCP_NODELAY IPTOS_LOWDELAY
socket options = TCP_NODELAY IPTOS_LOWDELAY SO_RCVBUF=65535 SO_SNDBUF=65535 SO_KEEPALIVE
workgroup = WORKGROUP
domain master = yes
client plaintext auth = yes
client min protocol = NT1
server min protocol = NT1
lanman auth = yes
ntlm auth = yes

[public]
guest ok = yes
guest only = yes
path = /samba.ok/
browseable = yes
read only = no

[t]
guest ok = yes
guest only = yes
path = /t
browseable = yes
read only = no


It seems that the lanman authorization is due to expire
so the problems may return. Nothing seemed to work
without the client plaintext auth = yes
line.