[Samba] Bad SMB2 signature on Samba 4

[Marcio Demetrio Bacci]

Hi

I'm using Samba 4.6.5 on Debian 8.

Recently, in samba Service appears problems with SMB2 SIGNATURE as the
message below:

root at dc2:/home/suporte# /etc/init.d/samba4 status
samba4.service - LSB: start Samba4 daemons
   Loaded: loaded (/etc/init.d/samba4)
   Active: active (exited) since Seg 2017-07-31 17:14:07 -03; 15h ago
  Process: 443 ExecStart=/etc/init.d/samba4 start (code=exited,
status=0/SUCCESS)

Ago 01 01:30:17 dc2 samba[486]: Exiting pid 486 on SIGTERM
Ago 01 01:30:17 dc2 samba[489]: [2017/08/01 01:30:17.667239,  0]
../source...m)
Ago 01 01:30:17 dc2 samba[489]: Exiting pid 489 on SIGTERM
Ago 01 01:30:17 dc2 samba[492]: [2017/08/01 01:30:17.666852,  0]
../source...m)
Ago 01 01:30:17 dc2 samba[492]: Exiting pid 492 on SIGTERM
Ago 01 01:30:17 dc2 samba[487]: [2017/08/01 01:30:17.667284,  0]
../source...m)
Ago 01 01:30:17 dc2 samba[487]: Exiting pid 487 on SIGTERM
Ago 01 01:30:17 dc2 samba[493]: Exiting pid 493 on SIGTERM
Ago 01 01:30:17 dc2 samba[491]: [2017/08/01 01:30:17.666900,  0]
../source...m)
Ago 01 01:30:17 dc2 samba[491]: Exiting pid 491 on SIGTERM
Hint: Some lines were ellipsized, use -l to show in full.
root at dc2:/home/suporte# tail /var/log/syslog
Aug  1 08:07:50 dc2 smbd[2601]:   [0000] 00 00 00 00 00 00 00 00   00 00 00
00 00 00 00 00   ........ ........
Aug  1 08:07:50 dc2 smbd[2601]: [2017/08/01 08:07:50.220014,  0]
../lib/util/util.c:555(dump_data)
Aug  1 08:07:50 dc2 smbd[2601]:   [0000] 97 0E 60 D4 29 8C C3 39   D1 19 5C
44 2F 11 BC 41   ..`.)..9 ..\D/..A
Aug  1 08:17:01 dc2 CRON[2652]: (root) CMD (   cd / && run-parts --report
/etc/cron.hourly)
Aug  1 08:43:15 dc2 smbd[2716]: [2017/08/01 08:43:15.604096,  0]
../libcli/smb/smb2_signing.c:171(smb2_signing_check_pdu)
Aug  1 08:43:15 dc2 smbd[2716]:   Bad SMB2 signature for message
Aug  1 08:43:15 dc2 smbd[2716]: [2017/08/01 08:43:15.604184,  0]
../lib/util/util.c:555(dump_data)
Aug  1 08:43:15 dc2 smbd[2716]:   [0000] 00 00 00 00 00 00 00 00   00 00 00
00 00 00 00 00   ........ ........
Aug  1 08:43:15 dc2 smbd[2716]: [2017/08/01 08:43:15.604206,  0]
../lib/util/util.c:555(dump_data)
Aug  1 08:43:15 dc2 smbd[2716]:   [0000] C2 06 72 B5 B7 B1 95 04   0E F5 4C
43 B5 18 13 15   ..r..... ..LC....

This way the Windows stations are having problems to authenticate
themselves. The login is taking a long time

Before, my Samba DC was work properly.

Follow my smb.conf file:


# Global parameters
[global]
 workgroup = EMPRESA
 realm = EMPRESA.COM.BR
 netbios name = DC2
 server role = active directory domain controller
 dns forwarder = 192.168.0.88,192.168.0.89
 idmap_ldb:use rfc2307 = yes
 ldap server require strong auth = no
 idmap config EMPRESA : unix_nss_info = yes
 winbind trusted domains only = no
 winbind use default domain = yes
 winbind enum users = yes
 winbind enum groups = yes
 winbind refresh tickets = yes


 template shell = /bin/bash
 template homedir = /home/%U


[netlogon]
 path = /usr/local/samba/var/locks/sysvol/empresa.com.br/scripts
 read only = No

[sysvol]
 path = /usr/local/samba/var/locks/sysvol
 read only = No
 acl_xattr:ignore system acls = yes