Linux Network Configuration

Linux Network Configuration in Linux/Centos

Today we will see in this post that How to set up network configuration in Linux/centos such as How to assign Static ip address, How to assign gateway, how to assign DNS, How to change hostname in linux. It's very easy to assign static ip address, DNS, Gateway and Host name. Please read full articles if you face any problem regarding this articles so please leave comments or drop email within 24 hours you will get reply by our team.

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To check hostname in Linux/Centos:

[root@localhost ONS]# hostname

To change hostname temporary in Linux/Centos:

[root@localhost ONS]# hostname newhostname

To change hostname permanent in Linux/Centos:

[root@localhost ONS]# vim /etc/sysconfig/network

NETWORKING=yes
HOSTNAME=localhost.local --------> please change localhost.local into newhostname.local (according to your requirement)

To restart network service in Linux/Centos:

[root@localhost ONS]# service network restart



To check ip address in Linux/Centos:

[root@localhost ONS]# ifoconfig

To assign static ip address temporary in Linux/Centos:

[root@localhost ONS]# ifconfig eth0 192.168.1.250 netmask 255.255.255.0

To assign static ip address permanent in Linux/Centos:

[root@localhost ONS]# vim /etc/sysconfig/network-scripts/ifcfg-eth0

View this detail

DEVICE="eth0"
BOOTPROTO="DHCP" 
HWADDR="00:0C:29:56:4E:9E"
MTU="1500"
NM_CONTROLLED="yes"
ONBOOT="yes"

Change some configuration:

DEVICE="eth0"
BOOTPROTO="static"
HWADDR="00:0C:29:56:4E:9E"
IPADDR=192.168.1.253
NETMASK=255.255.255.0 or PREFIX=24
MTU="1500"
NM_CONTROLLED="yes"
ONBOOT="yes"

To restart network service in Linux/Centos: 

[root@localhost ONS]# service network restart

To assign Gateway ip address in Linux/Centos: 

[root@localhost ONS]# vim /etc/sysconfig/network

NETWORKING=yes
HOSTNAME=localhost.local
GATEWAY=192.168.1.1

To assign DNS ip address in Linux/Centos:

[root@localhost ONS]# vim /etc/resolv.conf

nameserver 192.168.1.1 or 8.8.8.8

To restart network service in Linux/Centos: 

[root@localhost ONS]# service network restart

Note: Please don't forgot to restart service of network because it will update own recent changes.

Hope this will help to all of you and resolved your all query if you have any query or question so you may ask on email our email account (onlinenetworkssolution@gmail.com) or leave comment on page.

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Top 18 DNS Interview Questions and Answers

Top 18 DNS Interview Questions and Answers

Q1: What is DNS?

Ans: DNS stand for Domain Name System/Service. It’s used to resolve FQDN (Fully qualified domain name) to IP address and Vice versa such as www.example.com to 184.59.51.27 and vice versa.

Q2: How many types of DNS?

Ans:  There are two types of DNS server:

1.       Authoritative DNS

2.       Non-Authoritative DNS

Q3: How many types of zone in DNS?

Ans: There are three types of Zone in DNS:

1.       Primary Zone

2.       Secondary Zone

3.       Stub Zone

Q4: What is stub zone?

Ans: Stub zone contains Name Server record, SOA and SRV information of network which helps to resolve fast query and assign best path.

Q5: What is Secondary zone and how does it different from primary zone?

Ans: Secondary zone is copy of primary zone, it’s contain read only database of primary zone whereas primary zone contains main database of DNS Server. when primary zone fail to respond then secondary zone resolve client query. It’s means fault tolerance also.

Q6: How many lookup zone in DNS?

Ans: There are two lookup zone in DNS:

1.       Forward lookup zone

2.       Reverse lookup zone

Q7: What is forward lookup zone?

Ans: Forward lookup zone helps to resolve name (www.example.com) to IP address (61.95.235.79). A record creates in forward lookup zone.

Q8: What is Reverse lookup zone?

Ans: Reverse lookup zone helps to resolve IP Address (104.211.37.48) to name (www.example.com). PTR record creates in Reverse Lookup Zone.

Q9: How many records in DNS server?

Ans:  There are six records in DNS Server:

1.       A, AAA Record

2.       PTR Record

3.       CName/Alias Record

4.       SRV Record

5.       SOA Record

6.       MX Record

Q10: What is A record?

Ans: A record is used to resolve Name (www.example.com) to IP Address (61.95.234.98). It creates in Forward lookup zone.

Q11: What is difference between A record and AAAA record?

Ans:  A record called as host record also. It is used to resolve Name to IP Address in IPv4 Address while AAAA record same work but it use in IPv6 Address.

Q12: What is PTR record?

Ans: PTR stand for Pointer record. It is used to resolve IP Address to name like www.example.com to 61.95.125.45. It creates in Reverse lookup zone.

Q13: What is SOA?

Ans:  SOA stand for Start of Authority record. It record is information of DNS zone about that zone and about other zone. Each zone contains single SOA record.

Q14: What is SRV record?

Ans: SRV stand for Service locator record. It contains of all service information of DNS Server like port, target, priority and so on.  

Q15: What is CName/ Alias record?

Ans: Canonical Name/Alias record is used to specify that a domain name is an alias for another domain such as host name test.example.com alias name www.example.com.

Q16: What is MX record?

Ans: Mx stand for Mail Exchanger record. This record use in mail server and responsible for accepting email messages on behalf of recipient’s domain.

Q17: Which port is used by DNS server?

Ans: Port: 53

Q18: What is the Name server and how to identify it?

Ans: Nameserver is a server on the internet to handle queries regarding the location of a domain name's various services. They allow using domains instead of IP addresses.

Q19: What is Round Robin DNS?

Ans: Round Robin DNS is technique which used to load distribution, load balancing or fault-tolerance Internet protocol service host like FTP server, webserver and manage the DNS response to address requests from client computers.

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To create a secondary DNS zone

How to create secondary DNS on window server?

1.     Open DNS and in the DNS snap-in, Right click on the new domain controller in the console tree and select New Zone (dcl.local).

2.     Open New Zone dialog box and then click on Next to continue.

3.     Click on standard secondary zone as the Zone Type and then click on Next

4.     Select on Forward lookup zone and then click on Next

5.     Enter Zone Name _msdcs. forestrootdomain and then click on Next

6.     In the Master DNS Servers wizard then two DNS servers IP address in the forest in root domain and then click Next

7.     View your all setting which you required and then click on Finish.

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