How to install Gnome Desktop on Rhel 6

                               How to install Gnome Desktop in Rhel6 manually

If you using text login and now want to switch Graphical login then follow this steps.

1. First go to root
# su -

2. Now install X Window System and a graphical desktop environment. For example, to install the GNOME desktop environment, use this command:

# yum groupinstall "X Window System" Desktop

To install the KDE desktop environment, use:

# yum groupinstall "X Window System" "KDE Desktop"

3. Now change the run level to edit the /etc/inittab file:

# vi /etc/inittab

Find the line that includes the text initdefault. Change the numeral 3 to 5.

4 . Now run reboot system.

# reboot 

How to format pendrive in linux command line

                            How to format pendrive in linux command line

#First got to superuser mode and run the mention command.
1. root@linux~# su - root

#That will show all the volume of your hard disk.
2. root@linux~# fdisk -l

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1   976773167   488386583+  ee  GPT
Partition 1 does not start on physical sector boundary.

Disk /dev/sdc: 4010 MB, 4010803200 bytes
255 heads, 63 sectors/track, 487 cylinders, total 7833600 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0000fc03

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1   *        2048     7833599     3915776    c  W95 FAT32 (LBA)

In my system the usb drive is /dev/shc1

# umount /dev/sdc1
3. root@linux~# umount /dev/sdc1

# After you can format this pendrive which file system you want. I am going to format my pendrive with fat32 filesystem.
4. mkfs.vfat /dev/sdc1

How to configure openldap in RHel5

                     
                                          How to configure openldap Server on RHEL5

First install packages for openldap

root@bhandari#] yum install openldap-servers

Now set the ldap admin password

root@bhandari#] slappasswd
New password:
Re-enter new password:
{SSHA}WifrivWxRE4Mx2uupJ+e9kz2Pc2uFHQJ

Now switch to the mention location

root@bhandari#] cd /etc/openldap/

Open the configuration file and edit it

root@bhandari#] vim slapd.conf

database        bdb
suffix          "dc=example,dc=com"
rootdn          "cn=Manager,dc=example,dc=com"
rootpw          {SSHA}WifrivWxRE4Mx2uupJ+e9kz2Pc2uFHQJ

Now maintain database cache by using following command

root@bhandari#] cp DB_CONFIG.example /var/lib/ldap/DB_CONFIG

root@bhandari#] chown -Rf ldap:ldap /var/lib/ldap/

Now test our configuration by running this command

root@bhandari#] slaptest

Now start ldap service

root@bhandari#] /etc/init.d/ldap start;chkconfig ldap on

Create the users for ldap by using script.

root@bhandari#] vim user.sh
#!/bin/bash
for i in {1..10};do
useradd -d /home/domain/ldapuser$i ldapuser$i
echo "redhat"|passwd --stdin ldapuser$i > /dev/null
done

root@bhandari#] cat /etc/passwd | grep ldapuser > /root/passwd

root@bhandari#] cat /etc/group | grep ldapuser > /root/group

root@bhandari#] cd /usr/share/openldap/migration

root@bhandari#] vim migrate_common.ph
# Default base
$DEFAULT_BASE = "dc=example,dc=com";

root@bhandari#] ./migrate_passwd.pl /root/passwd > /root/passwd.ldif

root@bhandari#] ./migrate_group.pl /root/group > /root/group.ldif

Now create the base ldif file

root@bhandari#] vim base.ldif

dn: dc=example,dc=com
dc: example
objectClass: top
objectClass: domain

dn: ou=People,dc=example,dc=com
ou: People
objectClass: top
objectClass: organizationalUnit

dn: ou=Group,dc=example,dc=com
ou: Group
objectClass: top
objectClass: organizationalUnit

dn: ou=don,dc=example,dc=com
ou: don
objectClass: top
objectClass: organizationalUnit

First add base ldif in openldap database

root@bhandari#] ldapadd -x -W -D "cn=Manager,dc=example,dc=com" -f /root/base.ldif

Now add users and groups

root@bhandari#] ldapadd -x -W -D "cn=Manager,dc=example,dc=com" -f /root/passwd.ldif

root@bhandari#] ldapadd -x -W -D "cn=Manager,dc=example,dc=com" -f /root/group.ldif

we use nfs for sharing home directory to client machine.

root@bhandari#] yum install nfs

root@bhandari#] vim /etc/exports

/home/domain *(rw,sync)

root@bhandari#] /etc/init.d/nfs start;chkconfig nfs on

you can check ldap server users by run command

[root@bhandari#] ldapsearch -x -b "dc=example,dc=com"
# extended LDIF
#
# LDAPv3
# base <dc=example,dc=com> with scope subtree
# filter: (objectclass=*)
# requesting: ALL
#

# example.com
dn: dc=example,dc=com
dc: example
objectClass: top
objectClass: domain

# People, example.com
dn: ou=People,dc=example,dc=com
ou: People
objectClass: top
objectClass: organizationalUnit

# Group, example.com
dn: ou=Group,dc=example,dc=com
ou: Group
objectClass: top
objectClass: organizationalUnit

# don, example.com
dn: ou=don,dc=example,dc=com
ou: don
objectClass: top
objectClass: organizationalUnit

# ldapuser1, People, example.com
dn: uid=ldapuser1,ou=People,dc=example,dc=com
uid: ldapuser1
cn: ldapuser1
objectClass: account
objectClass: posixAccount
objectClass: top
objectClass: shadowAccount
userPassword:: e2NyeXB0fSQxJDc4Ri5INFN0JFQyOEhTdUg4UjJLVFJzYTN5S0RVaTA=
shadowLastChange: 15856
shadowMin: 0
shadowMax: 99999
shadowWarning: 7
loginShell: /bin/bash
uidNumber: 500
gidNumber: 500
homeDirectory: /home/domain/ldapuser1

# ldapuser2, People, example.com
dn: uid=ldapuser2,ou=People,dc=example,dc=com
uid: ldapuser2
cn: ldapuser2
objectClass: account
objectClass: posixAccount
objectClass: top
objectClass: shadowAccount
userPassword:: e2NyeXB0fSQxJGpHZERnWTdjJGx1Uk1Fa0svWGlkN2JqeWREdE0uMzE=
shadowLastChange: 15856
shadowMin: 0
shadowMax: 99999
shadowWarning: 7
loginShell: /bin/bash
uidNumber: 501
gidNumber: 501
homeDirectory: /home/domain/ldapuser2

# ldapuser3, People, example.com
dn: uid=ldapuser3,ou=People,dc=example,dc=com
uid: ldapuser3
cn: ldapuser3
objectClass: account
objectClass: posixAccount
objectClass: top
objectClass: shadowAccount
userPassword:: e2NyeXB0fSQxJDFiZGJxVk9YJEVZQkc3UldpTlAxS3B2cEhmNERxMy8=
shadowLastChange: 15856
shadowMin: 0
shadowMax: 99999
shadowWarning: 7
loginShell: /bin/bash
uidNumber: 502
gidNumber: 502
homeDirectory: /home/domain/ldapuser3

# ldapuser4, People, example.com
dn: uid=ldapuser4,ou=People,dc=example,dc=com
uid: ldapuser4
cn: ldapuser4
objectClass: account
objectClass: posixAccount
objectClass: top
objectClass: shadowAccount
userPassword:: e2NyeXB0fSQxJEJLalIxS2dJJER0T3ZtNEU5czZyOTNIVnhRSUNpMzE=
shadowLastChange: 15856
shadowMin: 0
shadowMax: 99999
shadowWarning: 7
loginShell: /bin/bash
uidNumber: 503
gidNumber: 503
homeDirectory: /home/domain/ldapuser4

# ldapuser5, People, example.com
dn: uid=ldapuser5,ou=People,dc=example,dc=com
uid: ldapuser5
cn: ldapuser5
objectClass: account
objectClass: posixAccount
objectClass: top
objectClass: shadowAccount
userPassword:: e2NyeXB0fSQxJEVCRlM5M3owJHVoS2xDQXNmUGh5cUI0Ni95ckVvNzA=
shadowLastChange: 15856
shadowMin: 0
shadowMax: 99999
shadowWarning: 7
loginShell: /bin/bash
uidNumber: 504
gidNumber: 504
homeDirectory: /home/domain/ldapuser5

# ldapuser6, People, example.com
dn: uid=ldapuser6,ou=People,dc=example,dc=com
uid: ldapuser6
cn: ldapuser6
objectClass: account
objectClass: posixAccount
objectClass: top
objectClass: shadowAccount
userPassword:: e2NyeXB0fSQxJHZ1RWNQZTYyJFpQRTQvZjI3ZnRncjJ4dzZFZ2JTYi8=
shadowLastChange: 15856
shadowMin: 0
shadowMax: 99999
shadowWarning: 7
loginShell: /bin/bash
uidNumber: 505
gidNumber: 505
homeDirectory: /home/domain/ldapuser6

# ldapuser7, People, example.com
dn: uid=ldapuser7,ou=People,dc=example,dc=com
uid: ldapuser7
cn: ldapuser7
objectClass: account
objectClass: posixAccount
objectClass: top
objectClass: shadowAccount
userPassword:: e2NyeXB0fSQxJHFSL0xIZUp0JDBmc3o4cnFhZFlQZHZ3WG5VTHAyeC8=
shadowLastChange: 15856
shadowMin: 0
shadowMax: 99999
shadowWarning: 7
loginShell: /bin/bash
uidNumber: 506
gidNumber: 506
homeDirectory: /home/domain/ldapuser7

# ldapuser8, People, example.com
dn: uid=ldapuser8,ou=People,dc=example,dc=com
uid: ldapuser8
cn: ldapuser8
objectClass: account
objectClass: posixAccount
objectClass: top
objectClass: shadowAccount
userPassword:: e2NyeXB0fSQxJFJQREJKc1lZJGJtYWtwR2FBTklnMHBSZE9ZSlNHVC8=
shadowLastChange: 15856
shadowMin: 0
shadowMax: 99999
shadowWarning: 7
loginShell: /bin/bash
uidNumber: 507
gidNumber: 507
homeDirectory: /home/domain/ldapuser8

# ldapuser9, People, example.com
dn: uid=ldapuser9,ou=People,dc=example,dc=com
uid: ldapuser9
cn: ldapuser9
objectClass: account
objectClass: posixAccount
objectClass: top
objectClass: shadowAccount
userPassword:: e2NyeXB0fSQxJGNCcW5ENnVpJGEyRmYwLmdnbmVacFIvQ1c3dEV6Vy8=
shadowLastChange: 15856
shadowMin: 0
shadowMax: 99999
shadowWarning: 7
loginShell: /bin/bash
uidNumber: 508
gidNumber: 508
homeDirectory: /home/domain/ldapuser9

# ldapuser10, People, example.com
dn: uid=ldapuser10,ou=People,dc=example,dc=com
uid: ldapuser10
cn: ldapuser10
objectClass: account
objectClass: posixAccount
objectClass: top
objectClass: shadowAccount
userPassword:: e2NyeXB0fSQxJE9BbDJRSTZ6JEhIVWpiTXZQb09XQko1cmNVVkdWUzA=
shadowLastChange: 15856
shadowMin: 0
shadowMax: 99999
shadowWarning: 7
loginShell: /bin/bash
uidNumber: 509
gidNumber: 509
homeDirectory: /home/domain/ldapuser10

# ldapuser1, Group, example.com
dn: cn=ldapuser1,ou=Group,dc=example,dc=com
objectClass: posixGroup
objectClass: top
cn: ldapuser1
userPassword:: e2NyeXB0fXg=
gidNumber: 500

# ldapuser2, Group, example.com
dn: cn=ldapuser2,ou=Group,dc=example,dc=com
objectClass: posixGroup
objectClass: top
cn: ldapuser2
userPassword:: e2NyeXB0fXg=
gidNumber: 501

# ldapuser3, Group, example.com
dn: cn=ldapuser3,ou=Group,dc=example,dc=com
objectClass: posixGroup
objectClass: top
cn: ldapuser3
userPassword:: e2NyeXB0fXg=
gidNumber: 502

# ldapuser4, Group, example.com
dn: cn=ldapuser4,ou=Group,dc=example,dc=com
objectClass: posixGroup
objectClass: top
cn: ldapuser4
userPassword:: e2NyeXB0fXg=
gidNumber: 503

# ldapuser5, Group, example.com
dn: cn=ldapuser5,ou=Group,dc=example,dc=com
objectClass: posixGroup
objectClass: top
cn: ldapuser5
userPassword:: e2NyeXB0fXg=
gidNumber: 504

# ldapuser6, Group, example.com
dn: cn=ldapuser6,ou=Group,dc=example,dc=com
objectClass: posixGroup
objectClass: top
cn: ldapuser6
userPassword:: e2NyeXB0fXg=
gidNumber: 505

# ldapuser7, Group, example.com
dn: cn=ldapuser7,ou=Group,dc=example,dc=com
objectClass: posixGroup
objectClass: top
cn: ldapuser7
userPassword:: e2NyeXB0fXg=
gidNumber: 506

# ldapuser8, Group, example.com
dn: cn=ldapuser8,ou=Group,dc=example,dc=com
objectClass: posixGroup
objectClass: top
cn: ldapuser8
userPassword:: e2NyeXB0fXg=
gidNumber: 507

# ldapuser9, Group, example.com
dn: cn=ldapuser9,ou=Group,dc=example,dc=com
objectClass: posixGroup
objectClass: top
cn: ldapuser9
userPassword:: e2NyeXB0fXg=
gidNumber: 508

# ldapuser10, Group, example.com
dn: cn=ldapuser10,ou=Group,dc=example,dc=com
objectClass: posixGroup
objectClass: top
cn: ldapuser10
userPassword:: e2NyeXB0fXg=
gidNumber: 509

# search result
search: 2
result: 0 Success

# numResponses: 25
# numEntries: 24

Thanks & Regards
Manish Bhandari

How to configure Yum server in Rhel5, Rhel6,

                                             How to configure Yum server in Rhel6

What is Yum Server?

YUM stands for Yellow dog Updater Modified, is a easy way to install, update  rpm packages on linux operating system and also there dependencies automatically.

Why is need?

In RHEL4 installing packages is a tedious process, some times its headache to install all the dependencies. So Red-hat come with a solution to overcome this dependencies problem in most situations, the solution for this is nothing but YUM implementation. This will resolve this dependency issue and other known issues.

In Rhel we can create two type of yum servers.

• Local yum server
• Sharing yum server  

Now I am going to configure local yum server.

1. First you create the directory where you copy the DVD.

root@localhost#] mkdir /yum

mount the DVD

root@localhost#] mount /media/DVD /yum
root@localhost#] cd /media/DVD
root@localhost#] cp -rv * /yum

now create the repo file for yum server

root@localhost#] vim /etc/yum.repos.d/server.repo
[yum]
name=yum
baseurl=file:///yum
enabled=1
gpgcheck=0

After you can check it by using this command

root@localhost#] yum list all

Now I am going to create sharing yum server in linux

We can use yum server in network as yum client through FTP and HTTP.

First you install vsftpd package for FTP

root@localhost#] rpm -ivh vsftpd

after that you mount the DVD as you want like mnt

root@localhots#] mount /media/DVD /mnt

and copy it into ftp default location.

root@localhost#] cd /mnt

root@localhost#] cp -rv * /var/ftp/pub

Now create the repo file in server

root@localhost#] vim /etc/yum.repos.d/server.repo
[server]
name=yum
baseurl=file:///var/ftp/pub
gpgcheck=0

Now if client want to use yum sverer then he can used through FTP or HTTP

On client side

root@localhost#] vim /etc/yum.repos.d/client.repo
[server]
name=yum
baseurl=ftp://192.168.2.1/pub/
gpgcheck=0

Now you can check it through command

root@localhost#] yum list all

We can do same from httpd

DNS Master and Slave Configuration

-->

DNS Server

DNS server is part of a global network of server that translate host name like www.facebook.com into numeraical IP address like 119.82.69.202 which computer on the Net use to communicate with each other. This is allow us to memorize or intuitive URLs and e-mail addresses instead of a long string of numbers.

Types of DNS Server.

• A master DNS server for your domain(s), which stores authoritative records for your domain.
• A slave DNS server, which relies on a master DNS server for data.
• A caching-only DNS server, which stores recent requests like a proxy server. It otherwise refers to other DNS servers.
• A forwarding-only DNS server, which refers all requests to other DNS servers.
  

Master DNS ( Primary DNS Server )

The authoritative server that contains the master zone file, which can be modified to update DNS information about the zone, is called the primary master server, or just master server.

Slave DNS ( Secondary DNS Server )

The additional name servers for the zone are called secondary servers or slave servers. Secondary servers retrieve information about the zone through a zone transfer from the master server or from another secondary server. DNS information about a zone is never modified directly on the secondary server.

Here I am using RHEL 5.5 64 bit operating System.

Domain name is = facebook.com

Master IP = 10.64.10.1 and host name is = server.example.com

Slave IP = 10.64.10.2 and host name is = slave.example.com

client IP = 10.64.10.3 and host name is = client.example.com

How to Setup Master DNS ( Primary DNS) Server.

First we check some file.

[root@server ~]# cat /etc/sysconfig/network

[root@server ~]# cat /etc/resolv.conf

[root@server ~]# cat /etc/hosts

Install Required RPMs.

[root@server ~] # yum install bind* caching-nameserver

[root@server ~]# /etc/init.d/named restart;chkconfig named on ( restart the service and make it permanent running )

Make the named.conf file and sysmbol link.

[root@server ~]# cd /var/named/chroot/etc/

[root@server etc]# cp -p named.caching-nameserver.conf named.conf

[root@server etc]# ln -s /var/named/chroot/etc/named.conf /etc/named.conf

[root@server etc]# ls -la /etc/named.conf

lrwxrwxrwx 1 root root 32 Dec 22 16:39 /etc/named.conf -> /var/named/chroot/etc/named.conf

Now Generate the Key. Edit it into named.conf

[root@server etc]# rndc-confgen -a -b 512

include “/etc/rndc.key”;

Now Edit the named.conf file.

options { listen-on port 53 { 127.0.0.1; 10.64.10.1; }; listen-on-v6 port 53 { ::1; }; directory "/var/named"; dump-file "/var/named/data/cache_dump.db"; statistics-file "/var/named/data/named_stats.txt"; memstatistics-file "/var/named/data/named_mem_stats.txt"; allow-query { localhost; 10.64.10.0/24; }; allow-query-cache { localhost; 10.64.10.0/24; }; }; logging { channel default_debug { file "data/named.run"; severity dynamic; }; }; view localhost_resolver { match-clients { localhost; 10.64.10.0/24; }; match-destinations { localhost; 10.64.10.0/24; }; recursion yes; include "/etc/named.rfc1912.zones"; }; include “/etc/rndc.key”;

Now mention the zone files in.

[root@server etc]# vim named.rfc1912.zones

zone "facebook.com" IN { type master; file "facebook.com.zone"; allow-update { none; }; allow-transfer { 10.64.10.2; }; }; zone "10.64.10.in-addr.arpa" IN { type master; file "rev-facebook.com.zone"; allow-update { none; }; allow-transfer { 10.64.10.2; }; };

Now create fowared zones files.

[root@server ~]# cd /var/named/chroot/var/named/

[root@server named]# cp -p localhost.zone facebook.com.zone

$TTL 86400 @ IN SOA master.facebook.com. root.facebook.com. (                                                           42 ; serial (d. adams)                                                           3H ; refresh                                                         15M ; retry                                                           1W ; expiry                                                          1D ) ; minimum                    IN NS master.facebook.com.                       IN NS slave.facebook.com. master       IN    A   10.64.10.1 slave          IN    A   10.64.10.2 client          IN    A  10.64.10.3

Now create reverse zone file.

[root@server named]# cp -p named.local rev-facebook.com.zone

$TTL 86400 @ IN SOA master.facebook.com. root.master.facebook.com. (                                                                               42 ; Serial                                                                          28800 ; Refresh                                                                           14400 ; Retry                                                                        3600000 ; Expire                                                                         86400 ) ; Minimum                  IN NS master.facebook.com.                 IN NS slave.facebook.com. 1               IN    PTR    master. 2               IN   PTR     slave. 3               IN   PTR    client.

Now Restart service.

[root@server named]# /etc/init.d/named restart

Stopping named:                               [ OK ]

Starting named:                                [ OK ]

Now check Master is running file.

[root@server named]# nslookup 10.64.10.1 Server: 10.64.10.1 Address: 10.64.10.1#53 1.10.64.10.in-addr.arpa name = master.

Or

[root@server named]# nslookup master.facebook.com Server: 10.64.10.1 Address: 10.64.10.1#53 Name: master.facebook.com Address: 10.64.10.1

Or

[root@server named]# dig -x 10.64.10.1 ; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_4.2 <<>> -x 10.64.10.1 ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 17417 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2 ;; QUESTION SECTION: ;1.10.64.10.in-addr.arpa. IN PTR ;; ANSWER SECTION: 1.10.64.10.in-addr.arpa. 86400 IN PTR master. ;; AUTHORITY SECTION: 10.64.10.in-addr.arpa. 86400 IN NS slave.facebook.com. 10.64.10.in-addr.arpa. 86400 IN NS master.facebook.com. ;; ADDITIONAL SECTION: slave.facebook.com. 86400 IN A 10.64.10.2 master.facebook.com. 86400 IN A 10.64.10.1 ;; Query time: 1 msec ;; SERVER: 10.64.10.1#53(10.64.10.1) ;; WHEN: Tue Dec 25 06:04:19 2012 ;; MSG SIZE rcvd: 146

That means master is running fine.

How to Setup Slave DNS ( Secondary DNS) Server.

Install Required RPMs.

[root@slave ~] # yum install bind* caching-nameserver

[root@slave ~]# /etc/init.d/named restart;chkconfig named on ( restart the service and make it permanent running )

Make the named.conf file and sysmbol link.

[root@slave ~]# cd /var/named/chroot/etc/

[root@slave etc]# cp -p named.caching-nameserver.conf named.conf

[root@slave etc]# ln -s /var/named/chroot/etc/named.conf /etc/named.conf

[root@slave etc]# ls -la /etc/named.conf

lrwxrwxrwx 1 root root 32 Dec 22 16:39 /etc/named.conf -> /var/named/chroot/etc/named.conf

Now Generate the Key. Edit it into named.conf

[root@slave etc]# rndc-confgen -a -b 512

include “/etc/rndc.key”;

Now Edit the named.conf file.

options { listen-on port 53 { 127.0.0.1; 10.64.10.2; }; listen-on-v6 port 53 { ::1; }; directory "/var/named"; dump-file "/var/named/data/cache_dump.db"; statistics-file "/var/named/data/named_stats.txt"; memstatistics-file "/var/named/data/named_mem_stats.txt"; // Those options should be used carefully because they disable port // randomization // query-source port 53; // query-source-v6 port 53; allow-query { localhost; 10.64.10.0/24; }; allow-query-cache { localhost; 10.64.10.0/24; }; }; logging { channel default_debug { file "data/named.run"; severity dynamic; }; }; view localhost_resolver { match-clients { localhost; 10.64.10.0/24; }; match-destinations { localhost; 10.64.10.0/24; }; recursion yes; include "/etc/named.rfc1912.zones"; }; include “/etc/rndc.key”;

Now mention zone files.

[root@slave ~]# cd /var/named/chroot/etc/

[root@slave etc]# vim named.rfc1912.zones

zone "facebook.com" IN { type slave; file "slaves/facebook.com.zone"; masters { 10.64.10.1; }; }; zone "10.64.10.in-addr.arpa" { type slave; file "slaves/facebook.com.zone"; masters { 10.64.10.1; }; };

Now create the zones file.

[root@slave ~]# cd /var/named/chroot/var/named/slaves

[root@slave slaves]# vim facebook.com.zone

T$TL 86400 @ IN SOA master.facebook.com. root.facebook.com. ( 2010031200 ; Serial 28800 ; Refresh 14400 ; Retry 3600000 ; Expire 86400 ) ; Minimum

[root@slave slaves]# vim rev-facebook.com.zone

$TTL 86400 @ IN SOA master.facebook.com. root.facebook.com. (                                                                          42 ; serial (d. adams)                                                                         3H ; refresh                                                                       15M ; retry                                                                          1W ; expiry                                                                         1D ) ; minimum

Create the Symbol link

[root@slave ~]# ln -s /var/named/chroot/var/named/slaves/facebook.com.zone /var/named/slaves/facebook.com.zone

[root@slave ~]# ls -la /var/named/slaves/facebook.com.zone

lrwxrwxrwx 1 root root 52 Dec 25 06:27 /var/named/slaves/facebook.com.zone -> /var/named/chroot/var/named/slaves/facebook.com.zone

Now change the permission

[root@slave ~]# chown named.named /var/named/chroot/var/named/slaves/rev-facebook.com.zone

[root@slave ~]# ls -l /var/named/chroot/var/named/slaves/rev-facebook.com.zone

-rw-r----- 1 named named 175 Dec 24 15:00 /var/named/chroot/var/named/slaves/rev-facebook.com.zone

Now Restart the service.

[root@slave ~]# /etc/init.d/named restart

Stopping named: [ OK ]

Starting named: [ OK ]

Now check the slave is working file.

[root@slave ~]# nslookup 10.64.10.2 Server: 10.64.10.2 Address: 10.64.10.2#53 2.10.64.10.in-addr.arpa name = slave.

Or

[root@slave ~]# nslookup slave.facebook.com Server: 10.64.10.2 Address: 10.64.10.2#53 Name: slave.facebook.com Address: 10.64.10.2

Or

[root@slave ~]# dig -x 10.64.10.2 ; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_4.2 <<>> -x 10.64.10.2 ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 23303 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2 ;; QUESTION SECTION: ;2.10.64.10.in-addr.arpa. IN PTR ;; ANSWER SECTION: 2.10.64.10.in-addr.arpa. 86400 IN PTR slave. ;; AUTHORITY SECTION: 10.64.10.in-addr.arpa. 86400 IN NS master.facebook.com. 10.64.10.in-addr.arpa. 86400 IN NS slave.facebook.com. ;; ADDITIONAL SECTION: slave.facebook.com. 86400 IN A 10.64.10.2 master.facebook.com. 86400 IN A 10.64.10.1 ;; Query time: 2 msec ;; SERVER: 10.64.10.2#53(10.64.10.2) ;; WHEN: Tue Dec 25 06:38:56 2012 ;; MSG SIZE rcvd: 145

Now check the client side.

[root@client ~]# nslookup 10.64.10.1 Server: 10.64.10.1 Address: 10.64.10.1#53 1.10.64.10.in-addr.arpa name = master. [root@client ~]# nslookup 10.64.10.2 Server: 10.64.10.1 Address: 10.64.10.1#53 2.10.64.10.in-addr.arpa name = slave.

                                                                                               

                                                                                         Thanks & Regards

                                                                                         Manish Singh Bhandari

How to install a looback interface in Ubuntu 12.04

            
                    How to install a looback interface in Ubuntu 12.04

After successful installation of GNS3, we will install loopback adapter on our Ubuntu,Centos, Redhat and Fedora systems, so that we can telnet into your routers.

Loopback tap installation on Ubuntu 12.04

$ sudo –i
#apt-get install uml-utilities
#modprobe tun
#tunctl                                       ( This will create loopback interface tap0 )
#ifconfig tap0 10.64.10.100 netmask 255.0.0.0 up
#ifconfig

If you want to add one more loopback interface

#tunctl                                       ( This will create loopback interface tap1 )
#ifconfig tap1 10.64.10.100 netmask 255.0.0.0 up

Loopback tap installation on Centos/Redhat/Fedora.We need tunctl which is not available in our local repositories. So we’ll have to add RPMForge
repository. Steps to add this repo is given here

http://wiki.centos.org/AdditionalResources/Repositories/RPMForge (Steps are the same for other 2 distros as well)

Ok lets install tunctl

$ su -
Password:                                       (Type in your root password here)
# yum install tunctl
# modprobe tun
# cd /usr/sbin
#./tunctl                                     ( This will create loopback interface tap0 )
# /sbin/ifconfig tap0 10.100.100.100 netmask 255.255.255.0 up
# /sbin/ ifconfig                ( verify that tap0 is up and given ip is assigned.)

If you want to add one more loopback interface

#./tunctl                                        ( This will create loopback interface tap1 )
# /sbin/ifconfig tap1 10.100.101.100 netmask 255.255.255.0 up

Important: Add these lines to iptables

sudo iptables -I INPUT -j ACCEPT -i tap0
sudo iptables -I OUTPUT -j ACCEPT -o tap0

How to configure the DNS Server in RHEL5.5

DNS Server

The Domain Name Server plays an important role in making Internet traffic possible. A DNS server is part of a global network of servers that translate host names, like www.facebook.com, into numerical IP (Internet Protocol) addresses, like 208.20.202.20, which computers on the Net use to communicate with each other. This allows us to use easy to memorize or intuitive URLs and e-mail addresses instead of a long string of numbers.

The advantage of having your own DNS server is it can process requests for traffic on your internal network without having to rely on another DNS server outside of your network. All the traffic is localized on your secure and internal network. Basically, this is a security feature because your LAN is essentially "hidden" from the outside world.

Real Time's DNS Servers run on Linux, giving them the stability and reliability everyone needs. It's also very cost effective because, like other Linux servers, a Linux DNS server can run on less expensive hardware than other operating systems.

As part of the installation, Real Time will also configure the server to your needs and specifications while keeping security as a top priority. Since it is built and designed in house, the server can be completely customized.
 

-->

How to configure the DNS Server in RHEL5.5

[root@node1 ~]# yum install bind* caching-nameserver

[root@node1 ~]# /etc/init.d/named restart;chkconfig named on

[root@node1 ~]# cd /var/named/chroot/etc/

[root@node1 ~]# cp -p named.caching-nameserver.conf named.conf

[root@node1 ~]# vim named.rfc1912.zones

Copy two zone in this file;

zone "localhost" IN {

type master;

file "localhost.zone";

allow-update { none; };

};

zone "0.0.127.in-addr.arpa" IN {

type master;

file "named.local";

allow-update { none; };

};

[root@node1 ~]# vim named.conf

Change few things in this file:

// named.caching-nameserver.conf

//

// Provided by Red Hat caching-nameserver package to configure the

// ISC BIND named(8) DNS server as a caching only nameserver

// (as a localhost DNS resolver only).

//

// See /usr/share/doc/bind*/sample/ for example named configuration files.

//

// DO NOT EDIT THIS FILE - use system-config-bind or an editor

// to create named.conf - edits to this file will be lost on

// caching-nameserver package upgrade.

//

options {

listen-on port 53 { 127.0.0.1; 10.64.10.1; };

listen-on-v6 port 53 { ::1; };

directory "/var/named";

dump-file "/var/named/data/cache_dump.db";

statistics-file "/var/named/data/named_stats.txt";

memstatistics-file "/var/named/data/named_mem_stats.txt";

// Those options should be used carefully because they disable port

// randomization

// query-source port 53;

// query-source-v6 port 53;

allow-query { 10.64.10.1; };

};

##############################################

zone "node1.example.com" IN {

type master;

file "node1.fow.zone";

allow-update { none; };

};

zone "10.64.10.in-addr.arpa" IN {

type master;

##############################################

[root@node1 ~]# cd /var/named/chroot/var/named

[root@node1 ~]# cp -p localhost.zone node1.fow.zone

[root@node1 ~]# cp -p named.zero node1.rev.zone

[root@node1 ~]# vim node1.fow.zone

Before change in this file:

$TTL 86400

@ IN SOA @ root (

42 ; serial (d. adams)

3H ; refresh

15M ; retry

1W ; expiry

1D ) ; minimum

IN NS @

IN A 127.0.0.1

IN AAAA ::1

After change in this file:#####################################

$TTL 86400

@ IN SOA @ root (

42 ; serial (d. adams)

3H ; refresh

15M ; retry

1W ; expiry

1D ) ; minimum

IN NS @

IN A 127.0.0.1

IN AAAA ::1

NS node1.example.com

A 10.64.10.1

[root@node1 ~]# vim node1.rev.zone

Befor chane in this file.

$TTL 86400

@ IN SOA localhost. root.localhost. (

42 ; serial (d. adams)

3H ; refresh

15M ; retry

1W ; expiry

1D ) ; minimum

IN NS localhost.

###################################################

After chage in this file:

$TTL 86400

@ IN SOA node1.example.com root.node1.example.com (

42 ; serial (d. adams)

3H ; refresh

15M ; retry

1W ; expiry

1D ) ; minimum

1 IN NS node1.example.com

[root@node1 ~]# vim /etc/resolve.conf

nameserver 10.64.10.1

root@node1 ~]# /etc/init.d/named restart

Stopping named: . [ OK ]

Starting named: [ OK ]

How to check DNS Server is working

[root@node1 ~]# nslookup 10.64.10.1

Server: 10.64.10.1

Address: 10.64.10.1#53

1.10.64.10.in-addr.arpa name = node1.example.com.10.64.10.in-addr.arpa.

[root@node1 ~]# nslookup node1.example.com

Server: 10.64.10.1

Address: 10.64.10.1#53

Name: node1.example.com

Address: 10.64.10.1

Name: node1.example.com

Address: 127.0.0.1

Thanks & Regards

Manish Bhandari