<s>
Pi-hole	B-Application
is	O
a	O
Linux	B-Application
network-level	O
advertisement	O
and	O
Internet	O
tracker	O
blocking	O
application	B-Application
which	O
acts	O
as	O
a	O
DNS	B-Protocol
sinkhole	I-Protocol
and	O
optionally	O
a	O
DHCP	B-Protocol
server	I-Protocol
,	O
intended	O
for	O
use	O
on	O
a	O
private	B-Protocol
network	I-Protocol
.	O
</s>
<s>
It	O
is	O
designed	O
for	O
low-power	O
embedded	O
devices	O
with	O
network	O
capability	O
,	O
such	O
as	O
the	O
Raspberry	B-Operating_System
Pi	I-Operating_System
,	O
but	O
can	O
be	O
installed	O
on	O
almost	O
any	O
Linux	B-Application
machine	O
.	O
</s>
<s>
Pi-hole	B-Application
has	O
the	O
ability	O
to	O
block	O
traditional	O
website	O
advertisements	O
as	O
well	O
as	O
advertisements	O
in	O
unconventional	O
places	O
,	O
such	O
as	O
smart	B-Device
TVs	I-Device
and	O
mobile	O
operating	O
system	O
advertisements	O
.	O
</s>
<s>
The	O
Pi-hole	B-Application
project	O
was	O
created	O
by	O
Jacob	O
Salmela	O
as	O
an	O
open	B-License
source	I-License
alternative	O
to	O
AdTrap	O
in	O
2014	O
and	O
was	O
hosted	O
on	O
GitHub	O
.	O
</s>
<s>
Pi-hole	B-Application
makes	O
use	O
of	O
a	O
modified	O
dnsmasq	B-Protocol
called	O
FTLDNS	O
,	O
cURL	B-Language
,	O
lighttpd	B-Protocol
,	O
PHP	B-Application
and	O
the	O
AdminLTE	O
Dashboard	O
to	O
block	O
DNS	B-Protocol
requests	I-Protocol
for	O
known	O
tracking	O
and	O
advertising	O
domains	O
.	O
</s>
<s>
The	O
application	B-Application
acts	O
as	O
a	O
DNS	B-Protocol
server	I-Protocol
for	O
a	O
private	B-Protocol
network	I-Protocol
(	O
replacing	O
any	O
pre-existing	O
DNS	B-Protocol
server	I-Protocol
provided	O
by	O
another	O
device	O
or	O
the	O
ISP	O
)	O
,	O
with	O
the	O
ability	O
to	O
block	O
advertisements	O
and	O
tracking	O
domains	O
for	O
users	O
 '	O
devices	O
.	O
</s>
<s>
It	O
obtains	O
lists	O
of	O
advertisement	O
and	O
tracking	O
domains	O
from	O
a	O
configurable	O
list	O
of	O
predefined	O
sources	O
,	O
and	O
compares	O
DNS	B-Protocol
queries	I-Protocol
against	O
them	O
.	O
</s>
<s>
If	O
a	O
match	O
is	O
found	O
within	O
any	O
of	O
the	O
lists	O
,	O
or	O
a	O
locally-configured	O
blacklist	O
,	O
Pi-hole	B-Application
will	O
refuse	O
to	O
resolve	O
the	O
requested	O
domain	O
and	O
respond	O
to	O
the	O
requesting	O
device	O
with	O
a	O
dummy	O
address	O
.	O
</s>
<s>
Because	O
Pi-hole	B-Application
blocks	O
domains	O
at	O
the	O
network	O
level	O
,	O
it	O
is	O
able	O
to	O
block	O
advertisements	O
,	O
such	O
as	O
banner	O
advertisements	O
on	O
a	O
webpage	O
,	O
but	O
it	O
can	O
also	O
block	O
advertisements	O
in	O
unconventional	O
locations	O
,	O
such	O
as	O
on	O
Android	B-Application
,	O
iOS	B-Application
and	O
smart	B-Device
TVs	I-Device
.	O
</s>
<s>
Using	O
VPN	B-Application
services	O
,	O
Pi-Hole	B-Application
can	O
block	O
domains	O
without	O
using	O
a	O
DNS	B-Protocol
filter	O
setup	O
in	O
a	O
router	O
.	O
</s>
<s>
Any	O
device	O
that	O
supports	O
VPN	B-Application
can	O
use	O
Pi-Hole	B-Application
on	O
a	O
cellular	O
network	O
or	O
a	O
home	O
network	O
without	O
having	O
a	O
DNS	B-Protocol
server	I-Protocol
configured	O
.	O
</s>
<s>
The	O
nature	O
of	O
Pi-hole	B-Application
allows	O
it	O
to	O
also	O
block	O
website	O
domains	O
in	O
general	O
by	O
manually	O
adding	O
the	O
domain	O
name	O
to	O
a	O
blacklist	O
.	O
</s>
<s>
Pi-hole	B-Application
can	O
also	O
function	O
as	O
a	O
network	O
monitoring	O
tool	O
,	O
which	O
can	O
aid	O
in	O
troubleshooting	O
DNS	B-Protocol
requests	I-Protocol
and	O
network	O
faults	O
.	O
</s>
<s>
Pi-hole	B-Application
can	O
also	O
be	O
used	O
to	O
encourage	O
the	O
use	O
of	O
DNS	B-Protocol
over	I-Protocol
HTTPS	I-Protocol
for	O
devices	O
using	O
it	O
as	O
a	O
DNS	B-Protocol
server	I-Protocol
with	O
the	O
cloudflared	O
binary	O
provided	O
by	O
Cloudflare	B-Application
.	O
</s>
<s>
Pi-hole	B-Application
functions	O
similarly	O
to	O
a	O
network	B-Application
firewall	I-Application
,	O
meaning	O
that	O
advertisements	O
and	O
tracking	O
domains	O
are	O
blocked	O
for	O
all	O
devices	O
behind	O
it	O
,	O
whereas	O
traditional	O
advertisement	O
blockers	O
only	O
run	O
in	O
a	O
user	O
's	O
browser	O
,	O
and	O
remove	O
advertisements	O
only	O
on	O
the	O
same	O
machine	O
.	O
</s>
