<s>
Quad9	O
is	O
a	O
global	B-Operating_System
public	I-Operating_System
recursive	I-Operating_System
DNS	O
resolver	O
that	O
aims	O
to	O
protect	O
users	O
from	O
malware	O
and	O
phishing	O
.	O
</s>
<s>
Quad9	O
is	O
operated	O
by	O
the	O
Quad9	O
Foundation	O
,	O
a	O
Swiss	B-Protocol
public-benefit	O
,	O
not-for-profit	O
foundation	O
with	O
the	O
purpose	O
of	O
improving	O
the	O
privacy	O
and	O
cybersecurity	O
of	O
Internet	O
users	O
,	O
headquartered	O
in	O
Zurich	O
.	O
</s>
<s>
Quad9	O
is	O
entirely	O
subject	O
to	O
Swiss	B-Protocol
privacy	O
law	O
,	O
and	O
the	O
Swiss	B-Protocol
government	O
extends	O
that	O
protection	O
of	O
the	O
law	O
to	O
Quad9	O
's	O
users	O
throughout	O
the	O
world	O
,	O
regardless	O
of	O
citizenship	O
or	O
country	O
of	O
residence	O
.	O
</s>
<s>
Quad9	O
was	O
the	O
first	O
to	O
use	O
standards-based	O
strong	O
cryptography	O
to	O
protect	O
the	O
privacy	O
of	O
its	O
users	O
 '	O
DNS	O
queries	O
,	O
and	O
the	O
first	O
to	O
use	O
DNSSEC	B-Protocol
cryptographic	O
validation	O
to	O
protect	O
users	O
from	O
domain	B-Protocol
name	I-Protocol
hijacking	I-Protocol
.	O
</s>
<s>
Quad9	O
protects	O
users	O
 '	O
privacy	O
by	O
not	O
retaining	O
or	O
processing	O
the	O
IP	B-Protocol
address	I-Protocol
of	O
its	O
users	O
,	O
and	O
is	O
consequently	O
GDPR-compliant	O
.	O
</s>
<s>
Quad9	O
operates	O
recursive	O
name	O
servers	O
for	O
public	O
use	O
at	O
the	O
twelve	O
IP	B-Protocol
addresses	I-Protocol
listed	O
below	O
.	O
</s>
<s>
These	O
addresses	O
are	O
routed	O
to	O
the	O
nearest	O
operational	O
server	O
using	O
anycast	B-Protocol
routing	O
.	O
</s>
<s>
Quad9	O
supports	O
DNS	B-Protocol
over	I-Protocol
TLS	I-Protocol
over	O
port	O
853	O
,	O
DNS	B-Protocol
over	I-Protocol
HTTPS	I-Protocol
over	O
port	O
443	O
,	O
and	O
DNSCrypt	B-Protocol
over	O
port	O
443	O
.	O
</s>
