RedHat Related Exams
RH202 Exam
Dig Server1.example.com, Resolve to successfully through DNS Where DNS server is 172.24.254.254
Answer and Explanation:
#vi /etc/resolv.conf
nameserver 172.24.254.254
# dig server1.example.com
#host server1.example.com
DNS is the Domain Name System, which maintains a database that can help your computer translate domain names such as to IP addresses such as 216.148.218.197. As no individual DNS server is large enough to keep a database for the entire Internet, they can refer requests to other DNS servers.
DNS is based on the named daemon, which is built on the BIND (Berkeley Internet Name Domain) package developed through the Internet Software Consortium
Users wants to access by name so DNS will interpret the name into ip address. You need to specify the Address if DNS server in each and every client machine. In Redhat Enterprise Linux, you need to specify the DNS server into /etc/resolv.conf file.
After Specifying the DNS server address, you can verify using host, dig and nslookup commands.
Deny to all users except root to run cron schedule.
Answer and Explanation:
1.vi /etc/cron.allow
root
or
vi /etc/cron.deny
Write all user name to deny.
/etc/cron.allow, /etc/cron.deny file is used to control users to allow or deny. If /etc/cron.allow file is created only that users are allowed to run cron schedule. Another way to deny to users is /etc/cron.deny write all user name on single line.
There are more then 400 Computers in your Office. You are appointed as a System Administrator. But you don’t have Router. So, you are going to use your One Linux Server as a Router. How will you enable IP packets forward?
Answer and Explanation:
1. /proc is the virtual filesystem, we use /proc to modify the kernel parameters at running time.
# echo “1” >/proc/sys/net/ipv4/ip_forward
2. /etc/sysctl.conf when System Reboot on next time, /etc/rc.d/rc.sysinit scripts reads the file /etc/sysctl.conf. To enable the IP forwarding on next reboot also you need to set the parameter.
net.ipv4.ip_forward=1
Here 0 means disable, 1 means enable.