<s>
NetworkManager	B-Protocol
is	O
a	O
daemon	B-Operating_System
that	O
sits	O
on	O
top	O
of	O
libudev	B-Application
and	O
other	O
Linux	B-Operating_System
kernel	I-Operating_System
interfaces	O
(	O
and	O
a	O
couple	O
of	O
other	O
daemons	B-Operating_System
)	O
and	O
provides	O
a	O
high-level	O
interface	O
for	O
the	O
configuration	O
of	O
the	O
network	O
interfaces	O
.	O
</s>
<s>
NetworkManager	B-Protocol
is	O
a	O
software	O
utility	O
that	O
aims	O
to	O
simplify	O
the	O
use	O
of	O
computer	B-Architecture
networks	I-Architecture
.	O
</s>
<s>
NetworkManager	B-Protocol
is	O
available	O
for	O
Linux	O
kernel-based	O
and	O
other	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
.	O
</s>
<s>
To	O
connect	O
computers	O
with	O
each	O
other	O
,	O
various	O
communications	O
protocols	O
have	O
been	O
developed	O
,	O
e.g.	O
</s>
<s>
IEEE	O
802.3	O
(	O
Ethernet	O
)	O
,	O
IEEE	O
802.11	O
(	O
"	O
wireless	O
"	O
)	O
,	O
IEEE	O
802.15.1	O
(	O
Bluetooth	O
)	O
,	O
PPPoE	B-Protocol
,	O
PPPoA	B-Protocol
,	O
and	O
many	O
many	O
more	O
.	O
</s>
<s>
Each	O
participating	O
computer	O
must	O
have	O
the	O
suitable	O
hardware	O
,	O
e.g.	O
</s>
<s>
network	B-Protocol
card	I-Protocol
or	O
wireless	B-General_Concept
network	I-General_Concept
card	I-General_Concept
and	O
this	O
hardware	O
must	O
be	O
configured	O
accordingly	O
to	O
be	O
able	O
to	O
establish	O
a	O
connection	O
.	O
</s>
<s>
In	O
case	O
of	O
a	O
monolithic	O
kernel	B-Operating_System
all	O
the	O
device	O
drivers	O
are	O
part	O
of	O
it	O
.	O
</s>
<s>
In	O
case	O
of	O
Linux	B-Operating_System
,	O
the	O
kernel	B-Operating_System
presents	O
for	O
each	O
device	O
driver	O
a	O
representation	O
in	O
form	O
of	O
a	O
device	B-Application
file	I-Application
.	O
</s>
<s>
All	O
device	B-Application
files	I-Application
are	O
found	O
in	O
the	O
/dev	B-Application
directory	O
,	O
and	O
traditionally	O
the	O
device	B-Application
files	I-Application
for	O
Ethernet	O
hardware	O
have	O
been	O
named	O
eth0	O
,	O
eth1	O
,	O
etc	O
.	O
</s>
<s>
Since	O
systemd	B-Application
,	O
they	O
are	O
named	O
differently	O
:	O
enp4s0	O
,	O
etc	O
.	O
</s>
<s>
(	O
This	O
abstraction	O
is	O
called	O
the	O
everything	B-Application
is	I-Application
a	I-Application
file	I-Application
concept	O
.	O
)	O
</s>
<s>
Anything	O
in	O
user-space	O
accesses	O
the	O
hardware	O
through	O
its	O
device	B-Application
file	I-Application
.	O
</s>
<s>
The	O
configuration	O
utility	O
to	O
configure	O
the	O
hardware	O
,	O
and	O
programs	O
like	O
the	O
web	O
browser/SSH/NTP-client/etc	O
.	O
</s>
<s>
On	O
Linux	B-Operating_System
and	O
all	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
,	O
the	O
utilities	O
ifconfig	B-Protocol
and	O
the	O
newer	O
ip	B-Protocol
(	O
from	O
the	O
iproute2-bundle	O
)	O
are	O
used	O
to	O
configure	O
IEEE	O
802.3	O
and	O
IEEE	O
802.11	O
hardware	O
.	O
</s>
<s>
These	O
utilities	O
configure	O
the	O
kernel	B-Operating_System
directly	O
and	O
the	O
configuration	O
is	O
applied	O
immediately	O
.	O
</s>
<s>
To	O
apply	O
the	O
same	O
static	O
configuration	O
after	O
each	O
boot-up	O
,	O
the	O
PID1-programs	O
are	O
used	O
:	O
System	B-Operating_System
V	I-Operating_System
init	I-Operating_System
executes	O
shell	B-Language
scripts	I-Language
and	O
binary	O
programs	O
,	O
systemd	B-Application
parses	O
its	O
own	O
conf-files	O
(	O
and	O
executes	O
programs	O
)	O
.	O
</s>
<s>
The	O
boot-up	O
configuration	O
for	O
network	O
interfaces	O
is	O
stored	O
in	O
/etc/network/interfaces	O
for	O
Debian	O
Linux	B-Operating_System
distributions	O
and	O
its	O
derivatives	O
or	O
ifcfg	O
files	O
in	O
/etc/sysconfig/network-scripts/	O
for	O
Fedora	O
and	O
its	O
derivatives	O
,	O
and	O
DNS-servers	O
in	O
/etc/resolv.conf	O
.	O
</s>
<s>
/etc/network/interfaces	O
or	O
/etc/sysconfig/network-scripts/ifcfg	O
-*	O
can	O
define	O
a	O
static	O
IP-address	O
or	O
dhclient	O
to	O
be	O
used	O
,	O
and	O
all	O
kinds	O
of	O
VPN	B-Application
can	O
be	O
configured	O
here	O
as	O
well	O
.	O
</s>
<s>
In	O
case	O
the	O
configuration	O
has	O
to	O
be	O
changed	O
,	O
DHCP-protocol	O
goes	O
a	O
long	O
way	O
to	O
do	O
so	O
automatically	O
,	O
without	O
the	O
user	O
even	O
noticing	O
.	O
</s>
<s>
NetworkManager	B-Protocol
is	O
accessible	O
via	O
dbus	B-Language
.	O
</s>
<s>
But	O
as	O
we	O
've	O
transitioned	O
from	O
physically	O
large	O
servers	O
to	O
more	O
portable	O
hosts	O
that	O
may	O
be	O
plugged	O
and	O
unplugged	O
(	O
or	O
moved	O
from	O
WiFi	O
hotspot	O
to	O
WiFi	O
hotspot	O
)	O
at	O
the	O
user	O
's	O
discretion	O
,	O
dynamic	O
configurations	O
(	O
i.e.	O
,	O
not	O
stored	O
in	O
a	O
static	O
configuration	O
file	O
but	O
taken	O
from	O
outside	O
the	O
host	O
,	O
and	O
potentially	O
changing	O
after	O
boot	O
)	O
have	O
become	O
a	O
more	O
prevalent	O
configuration	O
.	O
</s>
<s>
Bootp	B-Device
was	O
an	O
early	O
protocol	O
used	O
for	O
this	O
,	O
and	O
to	O
this	O
day	O
its	O
descendant	O
DHCP	B-Protocol
is	O
still	O
very	O
common	O
.	O
</s>
<s>
Many	O
Unix-like	B-Operating_System
systems	I-Operating_System
include	O
a	O
program	O
called	O
dhclient	O
to	O
handle	O
this	O
dynamic	O
configuration	O
.	O
</s>
<s>
NetworkManager	B-Protocol
has	O
two	O
components	O
:	O
</s>
<s>
several	O
graphical	B-Application
front-ends	O
for	O
diverse	O
graphical	B-Application
desktop	O
environments	O
,	O
such	O
as	O
GNOME	B-Language
Shell	I-Language
,	O
GNOME	B-Language
Panel	I-Language
,	O
KDE	B-Language
Plasma	I-Language
Workspaces	I-Language
,	O
Cinnamon	B-Language
,	O
etc	O
.	O
</s>
<s>
Both	O
components	O
are	O
intended	O
by	O
the	O
developers	O
to	O
be	O
reasonably	O
portable	O
,	O
and	O
the	O
applet	B-Language
is	O
available	O
to	O
desktop	O
environments	O
which	O
implement	O
the	O
Freedesktop.org	B-Application
System	O
Tray	O
Protocol	O
,	O
including	O
GNOME	B-Application
,	O
KDE	B-Language
Plasma	I-Language
Workspaces	I-Language
,	O
Enlightenment	B-Application
(	O
software	O
)	O
and	O
Xfce	B-Language
.	O
</s>
<s>
As	O
the	O
components	O
communicate	O
via	O
D-Bus	B-Language
,	O
applications	O
can	O
be	O
written	O
to	O
be	O
“	O
link-aware	O
”	O
,	O
or	O
to	O
replace	O
the	O
provided	O
applet	B-Language
entirely	O
.	O
</s>
<s>
One	O
example	O
is	O
KNetworkManager	B-Protocol
,	O
a	O
KDE	O
frontend	O
to	O
NetworkManager	B-Protocol
developed	O
by	O
Novell	O
for	O
SUSE	O
Linux	B-Operating_System
.	O
</s>
<s>
nm-applet	O
is	O
the	O
GNOME	B-Application
applet	B-Language
for	O
NetworkManager	B-Protocol
.	O
</s>
<s>
nmcli	O
is	O
NetworkManager	B-Protocol
's	O
built-in	O
command-line	B-Application
interface	I-Application
added	O
in	O
2010	O
.	O
nmcli	O
allows	O
easy	O
display	O
of	O
NetworkManager	B-Protocol
's	O
current	O
status	O
,	O
manage	O
connections	O
and	O
devices	O
,	O
monitor	O
connections	O
.	O
</s>
<s>
nmtui	O
is	O
a	O
built-in	O
text-based	B-Application
user	I-Application
interface	I-Application
.	O
</s>
<s>
cnetworkmanager	B-Protocol
command-line	B-Application
interface	I-Application
for	O
NetworkManager	B-Protocol
.	O
</s>
<s>
Antti	O
Kaijanmäki	O
announced	O
the	O
development	O
of	O
a	O
mobile	B-Protocol
broadband	I-Protocol
configuration	I-Protocol
assistant	I-Protocol
for	O
NetworkManager	B-Protocol
in	O
April	O
2008	O
;	O
it	O
became	O
available	O
in	O
NetworkManager	B-Protocol
version	O
0.7.0	O
.	O
</s>
<s>
Red	O
Hat	O
initiated	O
the	O
NetworkManager	B-Protocol
project	O
in	O
2004	O
with	O
the	O
goal	O
of	O
enabling	O
Linux	B-Operating_System
users	O
to	O
deal	O
more	O
easily	O
with	O
modern	O
networking	O
needs	O
,	O
particularly	O
wireless	B-Architecture
networking	I-Architecture
.	O
</s>
<s>
NetworkManager	B-Protocol
takes	O
an	O
opportunistic	O
approach	O
to	O
network	O
selection	O
,	O
attempting	O
to	O
use	O
the	O
best	O
available	O
connection	O
as	O
outages	O
occur	O
,	O
or	O
as	O
the	O
user	O
roams	O
between	O
wireless	O
networks	O
.	O
</s>
<s>
The	O
user	O
is	O
prompted	O
for	O
WEP	B-Protocol
or	O
WPA	O
keys	O
as	O
needed	O
.	O
</s>
<s>
The	O
NetworkManager	B-Protocol
project	O
was	O
among	O
the	O
first	O
major	O
Linux	B-Operating_System
desktop	O
components	O
to	O
utilize	O
D-Bus	B-Language
and	O
HAL	B-Application
extensively	O
.	O
</s>
<s>
Since	O
June	O
2009	O
,	O
however	O
,	O
NetworkManager	B-Protocol
no	O
longer	O
depends	O
on	O
HAL	B-Application
,	O
and	O
since	O
0.9.10	O
(	O
ca	O
.	O
</s>
<s>
2014	O
)	O
,	O
neither	O
does	O
it	O
require	O
the	O
D-Bus	B-Language
daemon	B-Operating_System
to	O
be	O
running	O
for	O
root	O
operation	O
.	O
</s>
