4. External Network
Warning
Ignore these steps when setting up the Temple HPC master. This interface is already configured and should NOT be changed. These steps are necessary when working on the MHPC lab.
4.1. Getting an dynamic IP using DHCP
To connect to the outside world and have internet our first
interface will have to obtain an IP via DHCP. ip addr
will
show you that the first interface (enp1s1f0
) does not have an
IP.
[root@master ~]# ip addr
...
2: enp1s1f0: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000
link/ether 00:14:4f:20:13:08 brd ff:ff:ff:ff:ff:ff
...
Run the DHCP client manually to ask for an IP:
[root@master ~]# dhclient enp1s1f0
After successful completion, you will see ip addr
reporting the assigned IP.
[root@master ~]# ip addr
...
2: enp1s1f0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:14:4f:20:13:08 brd ff:ff:ff:ff:ff:ff
inet 172.16.2.102/16 brd 172.16.255.255 scope global dynamic enp1s1f0
valid_lft 86390sec preferred_lft 86390sec
inet6 fe80::214:4fff:fe20:1308/64 scope link
valid_lft forever preferred_lft forever
...
4.2. Persistent dynamic IP configuration
Using dhclient
direcly is only a temporary measure. If we
reboot the system this configuration would be lost.
To make this permanent on RHEL/CentOS we need to modify files in the
/etc/sysconfig/network-scripts/
folder. Each interface has a
configuration file with the name ifcfg-INTERFACE
, e.g.,
ifcfg-enp1s1f0
. Open that file with a text editor and modify its
contents to the following.
TYPE=Ethernet
BOOTPROTO=dhcp
DEFROUTE=yes
NAME=enp1s1f0
DEVICE=enp1s1f0
ONBOOT=yes
This will configure the interface during boot with DHCP and obtain a dynamic IP. It will also grant us internet access.
Bring the interface down using the ifdown
command.
[root@master ~]# ifdown enp1s1f0
To bring it up use the ifup
command:
[root@master ~]# ifup enp1s1f0
Determining IP information for enp1s1f0... done.