<s>
Knot	B-Protocol
DNS	I-Protocol
is	O
an	O
open-source	B-Application
authoritative-only	O
server	B-Application
for	O
the	O
Domain	B-Protocol
Name	I-Protocol
System	I-Protocol
.	O
</s>
<s>
It	O
was	O
created	O
from	O
scratch	O
and	O
is	O
actively	O
developed	O
by	O
CZ.NIC	B-Protocol
,	O
the	O
.CZ	B-General_Concept
domain	O
registry	O
.	O
</s>
<s>
The	O
purpose	O
of	O
this	O
project	O
is	O
to	O
supply	O
an	O
alternative	O
open-source	B-Application
implementation	O
of	O
an	O
authoritative	O
DNS	B-Protocol
server	I-Protocol
suitable	O
for	O
TLD	O
operators	O
to	O
increase	O
overall	O
security	O
,	O
stability	O
and	O
resiliency	O
of	O
the	O
Domain	B-Protocol
Name	I-Protocol
System	I-Protocol
.	O
</s>
<s>
It	O
is	O
implemented	O
as	O
a	O
multi-threaded	O
daemon	O
,	O
using	O
a	O
number	O
of	O
programming	O
techniques	O
and	O
data	O
structures	O
to	O
make	O
the	O
server	B-Application
very	O
fast	O
,	O
notably	O
Read-copy-update	B-Operating_System
or	O
a	O
special	O
kind	O
of	O
a	O
radix	B-Data_Structure
tree	I-Data_Structure
.	O
</s>
<s>
Knot	B-Protocol
DNS	I-Protocol
uses	O
a	O
zone	O
parser	O
written	O
in	O
Ragel	B-Application
to	O
achieve	O
very	O
fast	O
loading	O
of	O
the	O
zones	O
at	O
the	O
startup	O
.	O
</s>
<s>
It	O
is	O
also	O
able	O
to	O
add	O
and	O
remove	O
zones	O
on	O
the	O
fly	O
by	O
changing	O
the	O
configuration	O
file	O
and	O
reloading	O
the	O
server	B-Application
using	O
the	O
'	O
knotc	O
 '	O
utility	O
.	O
</s>
<s>
Since	O
version	O
3.0.0	O
,	O
Knot	B-Protocol
DNS	I-Protocol
supports	O
a	O
high	O
performance	O
XDP	O
mode	O
in	O
Linux	O
,	O
which	O
can	O
improve	O
response	O
performance	O
significantly	O
.	O
</s>
<s>
New	O
in	O
1.2.0	O
:	O
Response	O
Rate	O
Limiting	O
,	O
Dynamic	B-Protocol
DNS	I-Protocol
,	O
and	O
a	O
new	O
remote	O
control	O
utility	O
.	O
</s>
<s>
New	O
in	O
1.3.0	O
:	O
new	O
zone	O
parser	O
in	O
Ragel	B-Application
(	O
replaces	O
zone	O
compilation	O
)	O
and	O
several	O
client	O
utilities	O
(	O
kdig	O
,	O
khost	O
and	O
knsupdate	O
)	O
.	O
</s>
<s>
New	O
in	O
1.4.0	O
:	O
automatic	O
DNSSEC	B-Protocol
signing	O
of	O
the	O
managed	O
zones	O
.	O
</s>
<s>
New	O
in	O
2.0.0	O
:	O
new	O
YAML-based	O
configuration	O
,	O
and	O
new	O
DNSSEC	B-Protocol
implementation	O
using	O
GnuTLS	B-Application
.	O
</s>
<s>
New	O
in	O
2.1.0	O
:	O
dynamic	O
configuration	O
,	O
PKCS	O
#11	O
interface	O
,	O
and	O
online	O
DNSSEC	B-Protocol
signing	O
.	O
</s>
<s>
New	O
in	O
2.2.0	O
:	O
Response	O
Rate	O
Limiting	O
white	O
listing	O
,	O
support	O
for	O
URI	O
(	O
RFC	O
7553	O
)	O
and	O
CAA	B-Protocol
(	O
RFC	O
6844	O
)	O
resource	O
record	O
types	O
,	O
interactive	O
mode	O
for	O
'	O
knotc	O
 '	O
,	O
new	O
control	O
interface	O
for	O
the	O
server	B-Application
including	O
simple	O
Python	O
bindings	O
.	O
</s>
<s>
New	O
in	O
2.3.0	O
:	O
DNSSEC	B-Protocol
signing	O
configured	O
in	O
server	B-Application
configuration	O
,	O
automatic	O
NSEC3	O
resalting	O
,	O
zone	O
operations	O
over	O
server	B-Application
control	O
interface	O
,	O
TLS	B-Protocol
in	O
kdig	O
.	O
</s>
<s>
New	O
in	O
2.4.0	O
:	O
Unified	O
LMDB	O
based	O
journal	O
,	O
new	O
statistics	O
module	O
,	O
automatic	O
deletion	O
of	O
retired	O
DNSSEC	B-Protocol
keys	O
.	O
</s>
<s>
New	O
in	O
2.6.0	O
:	O
On-slave	O
DNSSEC	B-Protocol
signing	O
,	O
automatic	O
DNSSEC	B-Protocol
algorithm	O
rollover	O
,	O
Ed25519	O
algorithm	O
support	O
,	O
TCP	B-Protocol
Fast	I-Protocol
Open	I-Protocol
.	O
</s>
<s>
New	O
in	O
2.7.0	O
:	O
Performance	O
improvement	O
,	O
new	O
module	O
for	O
DNS	B-Protocol
Cookies	O
,	O
new	O
module	O
for	O
GeoIP	B-Application
,	O
support	O
for	O
ECS	B-Protocol
.	O
</s>
<s>
New	O
in	O
2.8.0	O
:	O
Offline-KSK	O
,	O
multithreaded	O
DNSSEC	B-Protocol
signing	O
,	O
extended	O
ACL	O
for	O
DDNS	B-Protocol
,	O
zone	O
update	O
speed-up	O
.	O
</s>
<s>
New	O
in	O
2.9.0	O
:	O
Significant	O
zone	O
update	O
speed-up	O
,	O
TCP	B-Protocol
optimizations	O
,	O
configuration	O
cleanup	O
.	O
</s>
<s>
New	O
in	O
3.0.0	O
:	O
High	O
performance	O
XDP	O
mode	O
for	O
UDP	O
under	O
Linux	O
,	O
catalog	O
zones	O
support	O
,	O
continuous	O
DNSSEC	B-Protocol
validation	O
,	O
kzonesign	O
and	O
kxdpgun	O
utilities	O
,	O
DoH	B-Protocol
support	O
in	O
kdig	O
,	O
deterministic	O
ECDSA	O
support	O
,	O
on-line	O
backup	O
of	O
persistent	O
data	O
.	O
</s>
<s>
New	O
in	O
3.1.0	O
:	O
basic	O
DNS	B-Protocol
over	O
TCP	B-Protocol
using	O
XDP	O
,	O
routing-aware	O
XDP	O
processing	O
,	O
ZONEMD	O
generation	O
and	O
validation	O
,	O
SVCB/HTTPS	O
support	O
,	O
zone	O
catalog	O
evolution	O
,	O
EDNS	O
error	O
(	O
EDE	O
)	O
support	O
,	O
epoll/kqueue	O
support	O
.	O
</s>
<s>
New	O
in	O
3.2.0	O
:	O
full	O
DNS	B-Protocol
over	O
TCP	B-Protocol
using	O
XDP	O
(	O
including	O
transfers	O
)	O
,	O
DNS	B-Protocol
over	O
QUIC	B-Protocol
in	O
the	O
XDP	O
mode	O
,	O
DNSSEC	B-Protocol
multi-signer	O
support	O
.	O
</s>
