[Samba] Connection dropping every 24 hours from Windows Client.

[Rowland penny]

On 02/01/2020 17:45, hans via samba wrote:
> I posted the following a month ago but have only managed to get to fixing on this over the holidays.  Rowland mentions that I needed to add my domain info, it’s now included and I still have the same issue.
>
> Thanks and Happy New YearOld post begins below with edits
> Hello
>   
> I have a problem with my Windows 10 drive connections dropping every 24
> hours, very briefly.  It's enough to cause me to be unable to save my file,
> or access a geodatabase.  I have followed much trouble shooting and I
> believe that its due to the KDC Service ticket lifetime expiring, I have it
> set for 24 hours in smb.conf.
>
> I have a Samba 4.9 DC and an Ubuntu 18.04 member file server where the
> shares are running  4.7.6 and connected to the DC by Winbindd.  I notice
> that when my 24 hours is up, smbstatus will show that I have a new PID.  The
> files are unfortunately still being held open by the old PID and are no
> longer accessible (I think.).
>
> Here is the global part of my DC smb.conf
> [global]
>          workgroup = MYNET
>          realm = mynet.mynet.com
>          netbios name = MY_DC
>          server role = active directory domain controller
>          server services = s3fs, rpc, nbt, wrepl, ldap, cldap, kdc, drepl,
> winbind, ntp_signd, kcc, dnsupdate
>          idmap_ldb:use rfc2307 = yes
>          kdc:service ticket lifetime = 24
>          kdc:user ticket lifetime = 360
>          kdc:renewal lifetime = 1800
>          dsdb:schema update allowed = true
>          tls enabled  = yes
>          tls keyfile  = tls/myKey.pem
>          tls certfile = tls/myCert.pem
>          tls cafile   =
>          wins support = yes
>          ldap server require strong auth = no
>   
> And here is the global part of my file server smb.conf
>
> workgroup = MYNET
> client signing = yes
> client use spnego = yes
> kerberos method = secrets and keytab
> realm = MYNET.MYNET.COM
> security = ads
> vfs object = acl_xattr
> map acl inherit = yes
> hide unreadable = yes
> winbind refresh tickets = Yes
> idmap config * : backend = tdb
> idmap config * : range = 3000-7999
> idmap config MYNET : backend = rid     çadded as per Rowland
> idmap config MYNET : range = 50000-1000000  ç added as per Rowland
>
>
>                  winbind use default domain = true
>                  winbind offline logon = false
>                   winbind nss info = rfc2307
>                   winbind enum users = yes
>                  winbind enum groups = yes
>                  store dos attributes = yes
>   
> When I used to host the shares on the same DC, I never had this trouble.
> When I had kdc:service ticket lifetime = 10, then the connections dropped
> every 10 hours.  Do I just keep upping that number to something useful and
> hope I don't get hacked, or is there something else I am missing.  To me, it
> sounds a lot like this problem,
> https://lists.samba.org/archive/samba/2014-March/179555.html
>
> Thanks
>   

OK, you do not need these lines in your DC smb.conf:

         kdc:service ticket lifetime = 24
         kdc:user ticket lifetime = 360
         kdc:renewal lifetime = 1800
         dsdb:schema update allowed = true
         wins support = yes

Try this as the [global] part of your smb.conf on the Unix domain member:

[global]
workgroup = MYNET
security = ADS
realm = MYNET.MYNET.COM

dedicated keytab file = /etc/krb5.keytab
kerberos method = secrets and keytab

winbind use default domain = yes
winbind expand groups = 2
winbind refresh tickets = Yes

idmap config * : backend = tdb
idmap config * : range = 3000-7999
idmap config MYNET : backend = rid
idmap config MYNET : range = 50000-1000000

# If your users log into the Unix domain member
# uncomment the following two lines and alter to your requirements
#template shell = /bin/bash
#template homedir = /home/%U

username map = /etc/samba/user.map

vfs object = acl_xattr
map acl inherit = yes
store dos attributes = yes

client signing = yes

Create '/etc/samba/user.map' containing this:

!root = MYNET\Administrator

Run (as root):
net ads keytab create

Restart Samba and see how you go.

Rowland