displaying ip addresses:
[ashok@localhost ~]$ ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:fd:cb:90 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.101/24 brd 192.168.1.255 scope global dynamic eno16777736
valid_lft 85235sec preferred_lft 85235sec
inet6 fd84:6375:8789:0:20c:29ff:fefd:cb90/64 scope global noprefixroute dynamic
valid_lft 6865sec preferred_lft 3265sec
inet6 fe80::20c:29ff:fefd:cb90/64 scope link
valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN
link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN qlen 500
link/ether 52:54:00:05:c1:9d brd ff:ff:ff:ff:ff:ff
IP command may also be used to show stastics about network performances:
[ashok@localhost ~]$ ip -s link show eno16777736
2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000
link/ether 00:0c:29:fd:cb:90 brd ff:ff:ff:ff:ff:ff
RX: bytes packets errors dropped overrun mcast
247828 3430 0 0 0 0
TO show ip routing information:
[ashok@localhost ~]$ ip route
default via 192.168.1.1 dev eno16777736 proto static metric 100
192.168.1.0/24 dev eno16777736 proto kernel scope link src 192.168.1.101 metric 100
192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1
To test connectivity::
[ashok@localhost ~]$ ping -c1 192.168.1.101
PING 192.168.1.101 (192.168.1.101) 56(84) bytes of data.
64 bytes from 192.168.1.101: icmp_seq=1 ttl=64 time=0.192 ms
--- 192.168.1.101 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.192/0.192/0.192/0.000 ms
[ashok@localhost ~]$ ss -ta
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 5 192.168.122.1:domain *:*
LISTEN 0 128 *:ssh *:*
LISTEN 0 128 127.0.0.1:ipp *:*
LISTEN 0 100 127.0.0.1:smtp *:*
ESTAB 0 64 192.168.1.101:ssh 192.168.1.140:57710
LISTEN 0 128 :::ssh :::*
LISTEN 0 128 ::1:ipp :::*
LISTEN 0 100 ::1:smtp :::*
TX: bytes packets errors dropped carrier collsns
51345 479 0 0 0 0
Configuring network information with NMCLI:
to list all connections,add and list only active connections and many more:
TO list all connection:
[ashok@localhost ~]$ nmcli con show
NAME UUID TYPE DEVICE
virbr0 7ec8faaf-3b7a-4a92-9333-0a405e875b17 bridge virbr0
Wired connection 1 7a07cec3-1711-4715-8d0f-bc543a511ecc 802-3-ethernet --
eno16777736 d844d1c9-dac7-40dc-9cfe-ffc71461203e 802-3-ethernet eno16777736
To list all active connections::
[ashok@localhost ~]$ nmcli con show --active
NAME UUID TYPE DEVICE
virbr0 7ec8faaf-3b7a-4a92-9333-0a405e875b17 bridge virbr0
eno16777736 d844d1c9-dac7-40dc-9cfe-ffc71461203e 802-3-ethernet eno16777736
[ashok@localhost ~]$
to view the details of specific connections:
[ashok@localhost ~]$ nmcli con show eno16777736
connection.id: eno16777736
connection.uuid: d844d1c9-dac7-40dc-9cfe-ffc71461203e
connection.interface-name: eno16777736
connection.type: 802-3-ethernet
connection.autoconnect: yes
connection.autoconnect-priority: 0
connection.timestamp: 1454379297
connection.read-only: no
connection.permissions:
connection.zone: --
connection.master: --
connection.slave-type: --
connection.autoconnect-slaves: -1 (default)
connection.secondaries:
connection.gateway-ping-timeout: 0
connection.metered: unknown
802-3-ethernet.port: --
802-3-ethernet.speed: 0
802-3-ethernet.duplex: --
802-3-ethernet.auto-negotiate: yes
802-3-ethernet.mac-address: --
802-3-ethernet.cloned-mac-address: --
802-3-ethernet.mac-address-blacklist:
802-3-ethernet.mtu: auto
802-3-ethernet.s390-subchannels:
802-3-ethernet.s390-nettype: --
802-3-ethernet.s390-options:
802-3-ethernet.wake-on-lan: 1 (default)
802-3-ethernet.wake-on-lan-password: --
ipv4.method: auto
ipv4.dns:
ipv4.dns-search:
ipv4.addresses:
ipv4.gateway: --
ipv4.routes:
ipv4.route-metric: -1
ipv4.ignore-auto-routes: no
ipv4.ignore-auto-dns: no
ipv4.dhcp-client-id: --
ipv4.dhcp-send-hostname: yes
ipv4.dhcp-hostname: --
ipv4.never-default: no
ipv4.may-fail: yes
ipv6.method: auto
ipv6.dns:
ipv6.dns-search:
ipv6.addresses:
ipv6.gateway: --
ipv6.routes:
ipv6.route-metric: -1
ipv6.ignore-auto-routes: no
ipv6.ignore-auto-dns: no
ipv6.never-default: no
ipv6.may-fail: yes
ipv6.ip6-privacy: -1 (unknown)
ipv6.dhcp-send-hostname: yes
ipv6.dhcp-hostname: --
GENERAL.NAME: eno16777736
GENERAL.UUID: d844d1c9-dac7-40dc-9cfe-ffc71461203e
GENERAL.DEVICES: eno16777736
GENERAL.STATE: activated
GENERAL.DEFAULT: yes
GENERAL.DEFAULT6: no
GENERAL.VPN: no
GENERAL.ZONE: --
GENERAL.DBUS-PATH: /org/freedesktop/NetworkManager/ActiveConnection/0
GENERAL.CON-PATH: /org/freedesktop/NetworkManager/Settings/0
GENERAL.SPEC-OBJECT: /
GENERAL.MASTER-PATH: --
IP4.ADDRESS[1]: 192.168.1.101/24
IP4.GATEWAY: 192.168.1.1
IP4.DNS[1]: 208.59.247.45
IP4.DNS[2]: 208.59.247.46
IP4.DNS[3]: 192.168.1.1
IP4.DOMAIN[1]: cable.rcn.com
DHCP4.OPTION[1]: requested_domain_search = 1
DHCP4.OPTION[2]: requested_nis_domain = 1
DHCP4.OPTION[3]: requested_time_offset = 1
DHCP4.OPTION[4]: requested_broadcast_address = 1
DHCP4.OPTION[5]: requested_rfc3442_classless_static_routes = 1
DHCP4.OPTION[6]: requested_classless_static_routes = 1
DHCP4.OPTION[7]: requested_domain_name = 1
DHCP4.OPTION[8]: expiry = 1454463610
DHCP4.OPTION[9]: domain_name = cable.rcn.com
DHCP4.OPTION[10]: next_server = 0.0.0.0
DHCP4.OPTION[11]: broadcast_address = 192.168.1.255
DHCP4.OPTION[12]: dhcp_message_type = 5
DHCP4.OPTION[13]: requested_subnet_mask = 1
DHCP4.OPTION[14]: dhcp_lease_time = 86400
DHCP4.OPTION[15]: routers = 192.168.1.1
DHCP4.OPTION[16]: ip_address = 192.168.1.101
DHCP4.OPTION[17]: requested_static_routes = 1
DHCP4.OPTION[18]: requested_interface_mtu = 1
TO view the status of device and its details:
[ashok@localhost ~]$ nmcli dev status
DEVICE TYPE STATE CONNECTION
virbr0 bridge connected virbr0
eno16777736 ethernet connected eno16777736
virbr0-nic ethernet disconnected --
lo loopback unmanaged --
COnfiguring host name and name resolution ::
[root@localhost ~]# hostname
localhost.localdomain
[root@localhost ~]# hostnamectl set-hostname ashok.expanor.com
[root@localhost ~]# hostname
To check the status
[root@localhost ~]# hostnamectl status
Static hostname: ashok.expanor.com
Icon name: computer-vm
Chassis: vm
Machine ID: 544bc3a26e5840ce9f5be98967078dd4
Boot ID: 817341ebd2e647b48d6e10eed6183368
Virtualization: vmware
Operating System: CentOS Linux 7 (Core)
CPE OS Name: cpe:/o:centos:centos:7
Kernel: Linux 3.10.0-327.el7.x86_64
Architecture: x86-64
[root@localhost ~]# cat /etc/hostname
ashok.expanor.com
The host HOSTNAME used to test DNS server connectivity..
root@localhost ~]# host ashok.expanor.com
ashok.expanor.com has2.168.11.4i3 address 66.96.147.120
ashok.expanor.com mail is handled by 30 mx.expanor.com.
getent hosts hostname command is used to test host name resolution with the /etc/hosts..
root@localhost ~]# getent hosts ashok.expanor.com
66.96.147.120 ashok.expanor.com
practice exercises::
IPADRR=10.0.2.1 /etc/sysconfig/network-scripts/ifcfg-lab1
[root@ashok1 ~]# vi /etc/sysconfig/network-scripts/ifcfg-lab1
[root@ashok1 ~]# echo "PREFIX=24 /etc/sysconfig/network-scripts/ifcfg-lab1
> ^C
[root@ashok1 ~]# vi /etc/sysconfig/network-scripts/ifcfg-lab1
[root@ashok1 ~]# echo "IPADDR=10.0.2.1" >> /etc/sysconfig/network-scripts/ifcfg-lab1
[root@ashok1 ~]# vi /etc/sysconfig/network-scripts/ifcfg-lab1
[root@ashok1 ~]# echo "10.0.2.1 private " >> /etc/hosts
[root@ashok1 ~]# vi /etc/hosts
[root@ashok1 ~]# hostname
