<s>
Polipo	B-Protocol
is	O
a	O
lightweight	O
caching	B-Protocol
and	O
forwarding	O
web	O
proxy	B-Application
server	I-Application
.	O
</s>
<s>
It	O
has	O
a	O
wide	O
variety	O
of	O
uses	O
,	O
from	O
aiding	O
security	O
by	O
filtering	O
traffic	O
;	O
to	O
caching	B-Protocol
web	O
,	O
DNS	B-Protocol
and	O
other	O
computer	B-Architecture
network	I-Architecture
lookups	O
for	O
a	O
group	O
of	O
people	O
sharing	O
network	O
resources	O
;	O
to	O
speeding	O
up	O
a	O
web	B-Application
server	I-Application
by	O
caching	B-Protocol
repeated	O
requests	O
.	O
</s>
<s>
To	O
minimize	O
latency	O
,	O
Polipo	B-Protocol
both	O
pipelines	B-Protocol
multiple	O
resource	O
requests	O
and	O
multiplexes	B-Protocol
multiple	O
transactions	O
onto	O
the	O
same	O
TCP/IP	B-Protocol
connection	I-Protocol
.	O
</s>
<s>
Polipo	B-Protocol
is	O
HTTP	O
1.1-compliant	O
,	O
supports	O
IPv4	B-Protocol
,	O
IPv6	B-Protocol
,	O
traffic	O
filtering	O
and	O
privacy-enhancement	O
.	O
</s>
<s>
Polipo	B-Protocol
is	O
free	B-Application
software	I-Application
released	O
under	O
the	B-License
MIT	I-License
License	I-License
.	O
</s>
<s>
Polipo	B-Protocol
ceased	O
to	O
be	O
maintained	O
on	O
6	O
November	O
2016	O
due	O
to	O
the	O
increasingly	O
widespread	O
use	O
of	O
encryption	O
(	O
i.e.	O
</s>
<s>
HTTPS	B-Protocol
)	O
making	O
caching	B-Protocol
proxies	O
obsolete	O
.	O
</s>
<s>
Polipo	B-Protocol
is	O
designed	O
to	O
be	O
used	O
as	O
a	O
personal	O
web	B-Protocol
cache	I-Protocol
or	O
a	O
web	B-Protocol
cache	I-Protocol
shared	O
among	O
a	O
few	O
users	O
to	O
boost	O
internet	O
access	O
.	O
</s>
<s>
Because	O
of	O
this	O
,	O
it	O
has	O
been	O
put	O
to	O
uses	O
such	O
as	O
a	O
tether	O
on	O
the	O
OpenWrt	B-Application
.	O
</s>
<s>
Natively	O
,	O
polipo	B-Protocol
comes	O
as	O
a	O
highly	O
specialized	O
command-line	B-Application
interface	I-Application
(	O
CLI	O
)	O
software	O
application	O
,	O
which	O
requires	O
commands	O
to	O
be	O
typed	O
on	O
the	O
keyboard	B-Device
and	O
parameters	O
stored	O
in	O
configuration	O
text	O
files	O
.	O
</s>
<s>
Alternatively	O
,	O
polipo	B-Protocol
allows	O
users	O
to	O
run	O
the	O
program	O
automated	O
and	O
non-interactively	O
,	O
such	O
as	O
in	O
a	O
shell	B-Language
script	I-Language
.	O
</s>
<s>
By	O
starting	O
a	O
GUI	O
wrapper	O
application	O
users	O
can	O
intuitively	O
interact	O
with	O
polipo	B-Protocol
,	O
start	O
and	O
stop	O
it	O
and	O
change	O
its	O
working	O
parameters	O
,	O
through	O
graphical	O
icons	O
and	O
visual	O
indicators	O
.	O
</s>
<s>
The	O
fast	O
,	O
lightweight	O
and	O
small	O
memory	O
footprint	O
proxy	B-Application
server	I-Application
polipo	B-Protocol
uses	O
a	O
variety	O
of	O
techniques	O
:	O
</s>
<s>
Polipo	B-Protocol
will	O
upgrade	O
client	O
requests	O
to	O
HTTP/1.1	B-Protocol
even	O
if	O
they	O
come	O
in	O
as	O
old	O
HTTP/1.0	B-Protocol
.	O
</s>
<s>
Polipo	B-Protocol
does	O
HTTP	B-Protocol
1.1	I-Protocol
pipelining	O
well	O
,	O
so	O
it	O
can	O
enhance	O
internet	O
communication	O
latency	O
.	O
</s>
<s>
Polipo	B-Protocol
will	O
make	O
web	O
browsing	O
faster	O
or	O
at	O
least	O
appear	O
to	O
have	O
less	O
latency	O
.	O
</s>
<s>
Polipo	B-Protocol
will	O
cache	O
the	O
initial	O
segment	O
of	O
a	O
download	O
and	O
can	O
complete	O
it	O
later	O
using	O
Range	O
requests	O
,	O
in	O
case	O
of	O
interrupts	O
.	O
</s>
<s>
Polipo	B-Protocol
can	O
,	O
to	O
some	O
extent	O
,	O
substitute	O
for	O
filtering	O
and	O
privacy-enhancing	O
proxies	O
such	O
as	O
Privoxy	B-Language
or	O
WWWOFFLE	B-Protocol
,	O
it	O
provides	O
capabilities	O
to	O
block	O
or	O
redirect	O
requests	O
,	O
censor	O
HTTP	B-Protocol
request	O
headers	O
and	O
referrer	O
information	O
.	O
</s>
<s>
Polipo	B-Protocol
has	O
complete	O
support	O
for	O
IPv6	B-Protocol
.	O
</s>
<s>
Since	O
Polipo	B-Protocol
can	O
speak	O
both	O
IPv4	B-Protocol
and	O
IPv6	B-Protocol
,	O
Polipo	B-Protocol
can	O
be	O
used	O
as	O
a	O
bridge	O
between	O
the	O
IPv4	B-Protocol
and	O
IPv6	B-Protocol
Internets	I-Protocol
.	O
</s>
<s>
Polipo	B-Protocol
can	O
speak	O
the	O
SOCKS	B-Application
4	I-Application
and	I-Application
SOCKS	I-Application
5	I-Application
protocols	I-Application
.	O
</s>
<s>
Polipo	B-Protocol
serves	O
as	O
a	O
web	B-Protocol
cache	I-Protocol
.	O
</s>
<s>
Polipo	B-Protocol
is	O
limited	O
to	O
2G	O
or	O
4G	O
file	O
sizes	O
on	O
32	O
bit	O
systems	O
which	O
will	O
cause	O
errors	O
when	O
serving	O
large	O
requests	O
.	O
</s>
