RHCE 7 Exam Practice with Solution Part-1 (EX 300)

1) configure your systems that should be running Enforcing

Solution: 
[root@server ~]# vim /etc/selinux/config

SELINUX=enforcing

[root@server ~]# reboot

after reboot check that selinux status using following command

[root@server ~]# getenforce
Enforcing

Do the same for desktop machine also....

2) configure repository
--->create a repository for your virtual machines
--->The url is http://station.network0.example.com/content/rhel7.0/x86_64/dvd
Solution:
[root@server ~]# vim /etc/yum.repos.d/server.repos
[server]
name= Siratun Jannat
baseurl= http://station.network0.example.com/content/rhel7.0/x86_64/dvd
gpgcheck= 0

[root@server ~]# yum clean all
[root@server ~]# yum repolist

Do the same for desktop machine also....


3) ssh configuration
--->configure ssh access on your virtual machines as follows
--->clients witin my22ilt.org shouldnot access to ssh on your systems

Solution: 

[root@server ~]#yum install openssh-server
[root@server ~]#systemctl start sshd
[root@server ~]#yum enable sshd
[root@server ~]#firewall-cmd --permanent --add-service=ssh
[root@server ~]#firewall-cmd --reload
[root@server ~]#firewall-config
-->Permanent
-->Rich Rule
-->add-->ipv4 (family)
 -->element -->service -->ssh
 -->action -->reject
 -->source Address-->172.16.0.0/24    --(my22ilt.org )
--> reload firewalld

Now check firewall list that rules applied or not using following command

[root@server ~]#firewall-cmd --list-all

Do the same for desktop machine also....



       
4) configure port forwarding.

--->configure serverX to forward traffic incoming on port 80/tcp from desktop to port on 5243/tcp.

Solution:

[root@server ~]#firewall-config
-->Permanent
-->Rich Rule
-->add-->ipv4 (family)
 -->element -->port-forward
 -->source-->protocol-->tcp
-->port/port Range 5243
-->Local Forwarding 22
 -->source Address-->172.16.25.0/24    --(Server IP )
--> reload firewalld

[root@server ~]# firewall-cmd --list-all

 rich rules:
        rule family="ipv4" source address="172.16.25.0/24" forward-port port="5243" protocol="tcp" to-port="22"
[root@server ~]#



5) simple command
--->create a command called qsatat on both serverX and desktopX
--->It should able to execute the following command
(ps -eo pid,tid,class,rtprio,ni,pri,psr,pcpu,stat,wchan:14,comm)
---> The command should be executable by all users

Solution:

[root@server ~]#vim /etc/bashrc
qstat()
{
ps -eo pid,tid,class,rtprio,ni,pri,psr,pcpu,stat,wchan:14,comm
}
[root@server ~]#source /etc/bashrc
[root@server ~]#qstat

Do the same for desktop machine also....


6) configure ipv6 network

--->create eth0 with a static ipv6 addresses as follows
--->configure a static ipv6 address in serverX as fddb:fe2a:ab1e::c0a8:64/64
--->desktop as fddb:fe2a:ab1e::c0a8:02/64

Solution: 

--Server Machine---
[root@server ~]# nmcli connection modify eno16777736 ipv6.addresses fddb:fe2a:ab1e::c0a8:64/64 ipv6.method static connection.autoconnect yes
[root@server ~]# nmcli connection down eno16777736;nmcli connection up eno16777736
[root@server ~]#ping6 fddb:fe2a:ab1e::c0a8:64

--Desktop Machine---

[root@server ~]# nmcli connection modify eno16777736 ipv6.addresses fddb:fe2a:ab1e::c0a8:02/64 ipv6.method static connection.autoconnect yes
[root@server ~]# nmcli connection down eno16777736;nmcli connection up eno16777736
[root@server ~]#ping6 fddb:fe2a:ab1e::c0a8:02

Export Backup exclude table in Data Pump Error: ORA-39071

Error :

ORA-39001: invalid argument value
ORA-39071: Value for EXCLUDE is badly formed.
ORA-00911: invalid character


Solution:

[oracle@saidrasel]$ expdp system/password schemas= "exclude=TABLE:\"IN ('OUTWDCLR','INWARD_IMAGE')\"" directory=DATA_P dumpfile=MICR-20160512.dmp logfile=MICR-20160512.log EXCLUDE=STATISTICS CONTENT=ALL

ORA-31634 job already exists ORA-31664 unable to construct unique job name when defaulted

Error :

With the Partitioning, OLAP, Data Mining and Real Application Testing options
ORA-31634: job already exists

ORA-31664: unable to construct unique job name when defaulted

Reason:

DBA_DATAPUMP_JOBS table become equals to 99  for any particular schema thats why the error is coming

Solution:

Step 1: Execute the following query

select owner_name,job_name,operation,state from DBA_DATAPUMP_JOBS;

Step 2: If the output of the above query return 99 rows like as follows

SYSTEM SYS_EXPORT_SCHEMA_97 EXPORT                         NOT RUNNING
SYSTEM SYS_EXPORT_SCHEMA_98 EXPORT                         NOT RUNNING
SYSTEM SYS_EXPORT_SCHEMA_99 EXPORT                         NOT RUNNING

Step 3: Execute the following script

select 'DROP TABLE '||owner||'.'||table_name||';'
from dba_tables
where table_name like '%SYS%EXPORT%';

---Output Sample---

DROP TABLE SYSTEM.SYS_EXPORT_SCHEMA_01;
DROP TABLE SYSTEM.SYS_EXPORT_SCHEMA_02;
DROP TABLE SYSTEM.SYS_EXPORT_SCHEMA_03;
DROP TABLE SYSTEM.SYS_EXPORT_SCHEMA_04;

Step 4: Drop table from above output


Step 5: Re execute the backup script now.

If found any issues ...Please give me a buzz.....