Networking

UNIX SYSTEM ADM

Decimal to/from Binary

IpAddress, Subnet mask, Network prefix, Host identifier

network address(first address), broadcast address(last address)

Private networks 192.168.0.0/16 172.16.0.0/12 10.0.0.0/8

network address translation(NAT)

$ip link show $ip link show eth0 $sudo ip link set eth0 up $sudo ip addr add 152.18.n.n/12 dev eth0

$ip route show

$sudo ip route add default via 152.18.0.1

NETWORK ADDRESSING, SUPERUSER, CONFIGURE INTERFACE

$vi /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=eth0

BOOTPROTO=static

ONBOOT=yes

IPADDR=172.16.4.14

NETMASK=255.240.0.0

GATEWAY=172.16.0.1

$ifdown eth0 $ifup eth0

CONFIGURE INTERFACE

$host www.google.com //DNS lookup

$dig google.com A

$dig google.com MX

$dig 89.144.27.199.in-addr.arpa PTR

$nslookup www.google.com

$ dig google.com NS

$nslookup www.oreillyschool.com 199.27.148.66

DNS

$yum search ssh

$yum info openssh-clients

$sudo yum install openssh-clients

$sudo yum remove cdrdao

$yum list openssh-*

$rpm -ql openssh-clients

$sudo yum clean all

$sudo yum update

$sudo yum install openssh-server

$ssh localhost $sudo service sshd start $

YUM, RPM

$mkdir .ssh

$ssh-keygen

$cat .ssh/id_rsa.pub | ssh cold.useractive.com cat - ">>" .ssh/authorized_keys

$sftp cold.useractive.com $sftp>put sftp_test

$scp scp_test username@cold.useractive.com:~/

SSH

$head -n5 /etc/passwd

$less /etc/group

$sudo useradd foobar

$getent passwd foobar

$sudo less /etc/shadow

$sudo passwd foobar

$sudo groupadd -g 5555 testgroup

$getent group testgroup

$sudo usermod -G testgroup foobar

$groups foobar

$sudo usermod -G staff,employees foobar

$sudo groupdel employees

$sudo userdel -r foobar

$sudo $sudo –s

USER ACCOUNTS

ip link

ip route

dig

yum

rpm

ssh

host hostname nslookup useradd groupadd getent

SUMMARY