Root Passwd
a 1
space 1
setenforce 0
passwd
#init 5 or try #exit
other root----->passwd
Application-->system tool-->terminal
2) Enforcing mode
vi /etc/sysconfig/selinux
#touch /.autorelabel
#reboot
#getenforce
3) Setting IP Address
# cd /etc/sysconfig/network-scripts
#vi ifcfg-eth0
BROTOPROTP=static
DNS1=172.24.254.254
GATEWAY=172.24.254.254
IPADDR=172.24.254.6
NETMASK=255.255.0.0
NM_CONTROLLED=yes
ONBOOT=yes
:wq
#service network rstart
#ifconfig for checking IP Address
#route-n for checking gateway
cat /etc/resolve.conf
nameserver 172.24.254.254
ping 172.24.254.254 server
#nslookup instructor.example.com
NAME:instr.example
Address:172.24.254.254
4) #dig instructor.example.com
ANSWRER SECTION
instr.example.com 172.24.254.254
#host instructor.example.com
instructor.example..com 172.24.254.254
Grub problem:
Minimal Bash like editing is supported.For the first word, TAB list possible command completions. Anywhere else TAB lists possible device or file completion
grub>
solution:
grub> ls
1) Partition
100MB /mnt/new
#fdsik-l
#fdisk /dev/vd0
:p ----------> print
:n------------>new
p------------->primary
3------------->how many number
first cyclinder:9837
last cylinder +100M
:p---------->print /dev/vda3
:w
:reboot
#fdisk -l---------------------->To cross verify
mkfs -t ext4 /dev/vda3--------------------->format @ext4
note: man mkfs if block size asked
/block
n-->next
or
mkfs --help ---> if block size asked
#mkfs -t ext4 -b 4096 /dev/vda3 where, 4096 byte
mkdir -p /mnt/new ------------->Dir
#mount /dev/vda3 /mnt/new ----------->Temp
mount -a
#df-h----------> to verify
#vi /etc/fstab
/dev/vda3 /mnt/new ext4 defaults 02
:wq
#df -h
2) VG named examvg0 80MB extend size VG 16 MB
*) create a VG
1) partition
#fdisk -l
#fdisk /dev/vda
:p
:n
:e-------------->extended
first:10041
last <--- enter
:p
/dev/vda4 extended
:n
first: 10041
last:+80M
:p
:t
(1-5):5 /dev/vda5
:8e
:p
/dev/vda5 Linux LVM
:w
reboot
#fdisk -l --------------->to verity
#pvcreate /dev/vda5-------> To pvcreate
#vgcreate examvg0 /dev/vda5 [standard]
vgcreate --help
-s [physical extend size]
#vgcreate examvg0 -s 16 M /dev/vda5
#vgdisplay /examvgo------------->to confirm
note look at
PE size 16.00MiB
VG size 64.00MiB PV size multiple
Extend VG size
VG examvg0.............new size 100MB
#vgdisplay examvg0
create 36 partation
#pvcreate /dev/vda6
#vgextend examvg0 /dev/vda6 where, examvgo is vgname and /dev/vda6 is partition
#vgdisplay examvg0
4) logical volume ---------------->tetv0 vg --->testvg0
/data
Initial size lv ---------100MB
extend lv adding --->25 MB extend lv by 5 extend
*) Extend the logical volume
#df-h
#lvdisplay /dev/testvg0/textv0--> To See actual size
#vgdisplay testvg0--> To confirm sufficient space free PE/Size 24/96 (vaccum)
#lvextend -L +25M /dev/testvg0/testv0
#lvdisplay /dev/testvg0/testlv0----->To verify
#resize2fs /dev/testvg0/testvg0--------------> To resize
#df-h-----> To verify
extending lv by certain LV
#lvdisplay /dev/testvg0/testlv0--> To verify
#vgdisplay testvg0...................>To see Space
#lvextend -l +5 /dev/testvg0/testlv0-----------> extending by next 5 extend
#lvdisplay /dev/testvg0/testlv0
#df-h
mkdir/data
mount /dev/testvg0/textlv0 /data
#vi /etc/fstab
/dev/testvg0/testlv0 /data ext4 defaults 0 0
:x
df-h
Configuring caching-only DNS Server
only the hosts of local network 192.168.0.0/24 can access the DNS server
#rpm -q bind
#yum install bind
#vi /etc/named.conf
option {
listen-on port 53 { deny };
on -v6 port 53 { any };
allow-query { 192.168.0.0/24; };
#service names restart
#chkconfig named on
Deny FTP to selected login users
#useradd harry
#useradd andrew
#vi /etc/vsftpd/ftpusers
andrew
harry
:x
#service vsftpd start
#service chkconfig on
To test
ftp 192.168.0.104
root:andrew
login failed
setsebool -a \ grep ftp
ftp_home_dir=1
serverx to mount instruction.example.cpom:/var/ftp/pub as /local/package
Reboot:
Accessing nfs shared folders
#showmount -e instruction.example.com
#mkdir -p /local/package
#mount
#vi /etc/ffstab
at the bottom
instruction.example.cpm:/var/ftp/pub/local package nfs defaults 0 0
:x
#mount -a ----------> To active the fstab
#df-h
Allowing SSH access from specified host only
susan has remote SSH access to your machine from within example.com
clients within .remote.text should hot have
#rpm -q openssh-server
service sshd restart
chkconfig sshd on
#user add susan
vi /etc/hosts.deny
sshd : .remote.test
Allow only the users root and john through ssh
#useradd john
#vi /etc/ssh/sshd.config
write
AllowUser=root john
:x
service sshd restart
chkconfig ssh restart
To test
ssh root@ 192.168.0.250
ssh john@182.168.0.250
passwd:
exit
ssh student@ 192.168.0.250
permission denied.
Deny only the selected users using SSh
#vi /etc/ssh/sshd-config
DenyUser=john student
#service sshd restart
#chkconfig sshd restart
To test ssh student@192.168.0.250
passwd
permission denied
Configure your system such that all the logs generated in the local system is forwarded to the log server.
Configure rsyslog on your system to send all *.info log message to instruction.example.com
#rpm -q rsyslog
#vi /etc/rsyslog.conf
Go to the bottom
*.* @instructor.example.com
*.info @instruction.example.com
:x
service rsyslog restated
chkconfig rsyslog on
Configure on system as the central log server to accept logs forwarded by Remote Hosts.
#rpm -q rsyslog
#vi /etc/rsyslog.conf
/udp
#Mod Load imupd.so
#UDP ServerRun 514
Remove comment from (#Remove)
#service rsyslog restart
chkconfig rsyslog on
To test
tail /var/log/authentication
