Hi all,
I create this topic for our people who is interested in RHCE's subjects. Any issues/cases good for RHCE lab in any RHCE books will discuss.

First case:
Our topology for my lab:
Internet----pc1----pc2 - 192.168.114.0/24
|
|-----pc3 - 172.24.5.0/24 (connected to pc1 not the internet )
pc1=serverx.example.com
pc2=station1.example.com
pc1 is running as server to provide samba service, DNS server for 192.168.114.0, forwarding internet service to 2 local networks.
my case: pc2 can use samba service but pc3.
How i set samba up and troubleshoot:
I tried to build samba service for the network 192.168.114.0 to share /shared folder. I have no problem to use it in my local 192.168.114.0 network. But I also have want to use samba service in different network 172.24.5.0/24.
when i was at 172.24.5.6 computer:
[root@BT ~]# smbclient -L //serverx.example.com
Enter root's password:
protocol negotiation failed: NT_STATUS_INVALID_NETWORK_RESPONSE
[root@BT ~]# smbclient -L serverx.example.com
Enter root's password:
session request to SERVERX.EXAMPLE. failed (Not listening for calling name)
protocol negotiation failed: NT_STATUS_INVALID_NETWORK_RESPONSE
[root@BT ~]# smbclient //serverx.example.com/common -U kratos
Enter kratos's password:
session request to SERVERX.EXAMPLE. failed (Not listening for calling name)
protocol negotiation failed: NT_STATUS_INVALID_NETWORK_RESPONSE
Check the samba log on the server I saw it
[2013/08/23 04:13:32.099590, 0] lib/access.c:338(allow_access)
Denied connection from 172.24.5.6 (172.24.5.6)
I am for sure that open port for samba in fw and setup correct selinux and booleans for it.
The fact that we can connect and use samba service in 192.168.114.0 network.
/etc/samba/smb.conf
[shared]
path = /shared
read list = kratos
hosts allow = 172.24.5.0/255.255.255.0 192.168.114.0/255.255.255.0
On the 192.168.114.128 computer:
[kratos@station1 ~]$ smbclient //serverx.example.com/common -U kratos
Enter kratos's password:
Domain=[LLC] OS=[Unix] Server=[Samba 3.6.9-151.el6]
smb: \> ls
. D 0 Thu May 23 14:43:01 2013
.. DR 0 Thu Aug 15 11:25:22 2013
test 0 Thu May 23 14:43:01 2013

37380 blocks of size 4194304. 28979 blocks available
But we cannot use samba in different local network(172.24.5.0).
So my question is what is wrong that i can not use samba in different network ? What should i do to fix it ?
Thanks,

No, probably not. As has been mentioned to you before, you are NOT ALLOWED to discuss the contents of the RHCE test/labs, per the agreement you signed when you took it. Don't be surprised if the moderators close this thread.
You should go back to your networking basics. If you don't have a route from one network to the other, that will cause it to not work. If you don't allow traffic on that port to go through the firewall between those two networks...that will cause it not to work. Selinux restricting access?

Also, what diagnostics have you performed? What have you tried?

I wouldn't discuss about the RHCE test i want to discuss the lab/real case for the topic in the books for the RHCE only man.
[root@serverX station6]# ping 172.24.5.6
PING 172.24.5.6 (172.24.5.6) 56(84) bytes of data.
64 bytes from 172.24.5.6: icmp_seq=1 ttl=64 time=0.324 ms
64 bytes from 172.24.5.6: icmp_seq=2 ttl=64 time=0.353 ms
64 bytes from 172.24.5.6: icmp_seq=3 ttl=64 time=0.346 ms
64 bytes from 172.24.5.6: icmp_seq=4 ttl=64 time=0.308 ms
[root@BT ~]# ping serverx.example.com
PING serverx.example.com (192.168.114.129) 56(84) bytes of data.
64 bytes from serverx.example.com (192.168.114.129): icmp_seq=1 ttl=64 time=0.269 ms
64 bytes from serverx.example.com (192.168.114.129): icmp_seq=2 ttl=64 time=0.340 ms
64 bytes from serverx.example.com (192.168.114.129): icmp_seq=3 ttl=64 time=0.287 ms
^C
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:139
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:445
10 780 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:137
0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:138

I tried turn off the fw in the server then from pc3 :
#
[root@BT ~]# smbclient //serverx.example.com/common -U kratos
Enter kratos's password:
protocol negotiation failed: NT_STATUS_INVALID_NETWORK_RESPONSE
The same issue ....So it is not fw issue.
Also looking hint from /var/log/samba and see
[2013/08/22 16:17:07.062227, 0] lib/access.c:338(allow_access)
Denied connection from 172.24.5.6 (172.24.5.6)
[2013/08/22 16:17:58.297683, 0] lib/access.c:338(allow_access)
Denied connection from 172.24.5.6 (172.24.5.6)
[2013/08/22 16:17:58.296399, 0] lib/access.c:338(allow_access)
Denied connection from 172.24.5.6 (172.24.5.6)
[2013/08/22 16:17:58.313968, 0] lib/access.c:338(allow_access)
Denied connection from 172.24.5.6 (172.24.5.6)
samba_create_home_dirs --> off
samba_domain_controller --> off
samba_enable_home_dirs --> off
samba_export_all_ro --> on
samba_export_all_rw --> on
samba_portmapper --> off
samba_run_unconfined --> off
samba_share_fusefs --> off
samba_share_nfs --> off
sanlock_use_samba --> off
use_samba_home_dirs --> off
virt_use_samba --> off

and :
drwxr-xr-x. root root system_ubject_r:samba_share_t:s0 /shared/

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