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DNS

Rule 53: If you can think of it, someone's done it in the DNS

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Public DNS

A list of public DNS Servers

Provider IPv4 IPv6 DNS over HTTPS & TLS
AliDNS 223.5.5.5 / 223.6.6.6 HTTPS, TLS:
Alternate DNS 198.101.242.72 / 23.253.163.53 2602:fcbc::ad / 2001:4800:780e:510:a8cf:392e:ff04:8982 HTTPS, TLS
Cisco OpenDNS FamilyShield 208.67.222.123 / 208.67.220.123 2620:119:35::123 / 2620:119:53::123 HTTPS
Cisco OpenDNS Standards 208.67.222.222 / 208.67.220.220 2620:119:35::35 / 2620:119:53::53 HTTPS
CleanBrowsing Adult 185.228.168.10 / 185.228.169.11 2a0d:2a00:1::1 / 2a0d:2a00:2::1 HTTPS
CleanBrowsing Family 185.228.168.168 / 185.228.169.168 2a0d:2a00:1:: / 2a0d:2a00:2:: HTTPS
CleanBrowsing Security 185.228.168.9 / 185.228.169.9 2a0d:2a00:1::2 / 2a0d:2a00:2::2 HTTPS
Cloudflare 1.1.1.1 / 1.0.0.1 2606:4700:4700::1111 / 2606:4700:4700::1001 HTTPS
Comodo DNS 8.26.56.26 / 8.20.247.20 N/A N/A
Comodo Secure Internet Gateway 8.26.56.10 / 8.20.247.10 N/A N/A
ControlD Uncensored 76.76.2.5 / 76.76.10.5 2606:1a40::5 / 2606:1a40:1::5 HTTPS, TLS
ControlD Filter 76.76.2.4 / 76.76.10.4 2606:1a40::4 / 2606:1a40:1::4 HTTPS, TLS
Digital Courage 5.9.164.112 / 46.182.19.48 2a02:2970:1002::18 HTTPS
dns.watch 84.200.69.80 / 84.200.70.40 2001:1608:10:25::1c04:b12f / 2001:1608:10:25::9249:d69b HTTPS
Dyn DNS 216.146.35.35 / 216.146.36.36 N/A N/A
FreeDNS 172.104.237.57 / 37.235.1.177 N/A N/A
Google 8.8.8.8 / 8.8.4.4 2001:4860:4860::8888 / 2001:4860:4860::8844 HTTPS, TLS
Hurricane Electric 74.82.42.42 2001:470:20::2 N/A
OpenNIC 69.195.152.204 / 23.94.60.240 N/A N/A
Quad9 9.9.9.9 / 149.112.112.112 2620:fe::fe / 2620:fe::9 HTTPS, TLS
UncensoredDNS 91.239.100.100 / 89.233.43.71 2001:67c:28a4:: / 2a01:3a0:53:53:: HTTPS, HTTPS
Yandex.DNS Standard 77.88.8.8 / 77.88.8.1 N/A N/A
Yandex.DNS Safe 77.88.8.88 / 77.88.8.2 N/A N/A
Yandex.DNS Family 77.88.8.7 / 77.88.8.3 N/A N/A
DNS4EU 86.54.11.100 2a13:1001::86:54:11:100 N/A
DNS4EU Malware 86.54.11.1 2a13:1001::86:54:11:1 N/A
DNS4EU Malware+Ad 86.54.11.13 2a13:1001::86:54:11:13 N/A
DNS4EU Malware+Family 86.54.11.12 2a13:1001::86:54:11:12 N/A
DNS4EU Malware+Ad+Family 86.54.11.11 2a13:1001::86:54:11:11 N/A

DDNS service

DNS root zones

A list of DNS root zones:

Hostname IPv4 IPv6 Operator
a.root-servers.net 198.41.0.4 2001:503:ba3e::2:30 Verisign Inc.
b.root-servers.net 199.9.14.201 2001:500:200::b University of Southern California Information Sciences Institute
c.root-servers.net 192.33.4.12 2001:500:2::c Cogent Communications
d.root-servers.net 199.7.91.13 2001:500:2d::d University of Maryland
e.root-servers.net 192.203.230.10 2001:500:a8::e NASA (Ames Research Center)
f.root-servers.net 192.5.5.241 2001:500:2f::f Internet Systems Consortium Inc.
g.root-servers.net 192.112.36.4 2001:500:12::d0d US Department of Defense (NIC)
h.root-servers.net 198.97.190.53 2001:500:1::53 US Army (Research Lab)
i.root-servers.net 192.36.148.17 2001:7fe::53 Netnod
j.root-servers.net 192.58.128.30 2001:503:c27::2:30 Verisign Inc.
k.root-servers.net 193.0.14.129 2001:7fd::1 RIPE NCC
l.root-servers.net 199.7.83.42 2001:500:9f::42 ICANN
m.root-servers.net 202.12.27.33 2001:dc3::35 WIDE Project

More Services

DNS Services

DNS Provider

Other Lists

NTP

.'`~~~~~~~~~~~`'.
(  .'11 12 1'.  )
|  :10 \|   2:  |
|  :9   @   3:  |
|  :8       4;  |
'. '..7 6 5..' .'
 ~-------------~

List of NTP Servers:

Service URL
apple time.apple.com
apple time.euro.apple.com
apple time1.apple.com
apple time2.apple.com
apple time3.apple.com
apple time4.apple.com
apple time5.apple.com
apple time6.apple.com
apple time7.apple.com
AWS time.aws.com
berkeley ntp1.net.berkeley.edu
berkeley ntp2.net.berkeley.edu
cenam cronos.cenam.mx
Chinese Academy of Sciences ntp.ntsc.ac.cn
cloudflare time.cloudflare.com
colby ntp.colby.edu
colorado utcnist2.colorado.edu
columbia gnomon.cc.columbia.edu
dianacht ntp.dianacht.de
edu.cn ntp.neu.edu.cn
ehu ntp.i2t.ehu.eus
esa time.esa.int
esa time1.esa.int
EWETel ntp0.ewetel.de
EWETel ntp1.ewetel.de
facebook time.facebook.com
facebook time1.facebook.com
facebook time2.facebook.com
facebook time3.facebook.com
facebook time4.facebook.com
facebook time5.facebook.com
fau ntp1.fau.de
fau ntp2.fau.de
Freenet ntp0.freenet.de
Freenet ntp1.freenet.de
fu-berlin time.fu-berlin.de
fu-berlin zeit.fu-berlin.de
gatech navobs1.gatech.edu
Georgia State University ntp.gsu.edu
google time.google.com
google time1.google.com
google time2.google.com
google time3.google.com
google time4.google.com
gum tempus1.gum.gov.pl
gum tempus2.gum.gov.pl
he clock.nyc.he.net
he clock.sjc.he.net
hea ntp-galway.hea.net
Hetzner ntp1.hetzner.de
Hetzner ntp2.hetzner.de
Hetzner ntp3.hetzner.de
iiss asynchronos.iiss.at
in.ua ntp.time.in.ua
in.ua ntp2.time.in.ua
in.ua ntp3.time.in.ua
inrim ntp1.inrim.it
inrim ntp2.inrim.it
INTERNET MULTIFEED CO. ntp1.jst.mfeed.ad.jp
INTERNET MULTIFEED CO. ntp2.jst.mfeed.ad.jp
INTERNET MULTIFEED CO. ntp3.jst.mfeed.ad.jp
isc clock.isc.org (prev ntp.isc.o rg)
isi timekeeper.isi.edu
Kantonsschule Zug ntp0.as34288.net
Kantonsschule Zug ntp1.as34288.net
layer42 gps.layer42.net
lcf ntp.lcf.mx
liu timehost.lysator.liu.se
microsoft time.windows.com
mobatime ntp.mobatime.ru
MSK-IX ntp.ix.ru
mta ntp.atomki.mta.hu
Nat Morris ntp.nat.ms
neel ntp.neel.ch
netbone-digital ntpstm.netbone-digital.com
Netnod ntp.se
Netnod Göteborg gbg1.ntp.se
Netnod Göteborg gbg2.ntp.se
Netnod Malmö mmo1.ntp.se
Netnod Malmö mmo2.ntp.se
nic ntp.nic.cz
nict ntp.nict.jp
nict ntp.nict.jp
nist time-a-b.nist.gov
nist time-a-g.nist.gov
nist time-a-wwv.nist.gov
nist time-b-b.nist.gov
nist time-b-g.nist.gov
nist time-b-wwv.nist.gov
nist time-c-b.nist.gov
nist time-c-g.nist.gov
nist time-c-wwv.nist.gov
nist time-d-b.nist.gov
nist time-d-g.nist.gov
nist time-d-wwv.nist.gov
nist time.nist.gov
nist utcnist.colorado.edu
nist utcnist2.colorado.edu
nrc time.nrc.ca
NSU ntp.nsu.ru
NTP Pool 0.amazon.pool.ntp.org
NTP Pool 0.android.pool.ntp.org
NTP Pool 0.arch.pool.ntp.org
NTP Pool 0.asia.pool.ntp.org
NTP Pool 0.askozia.pool.ntp.org
NTP Pool 0.centos.pool.ntp.org
NTP Pool 0.debian.pool.ntp.org
NTP Pool 0.dragonfly.pool.ntp.org
NTP Pool 0.europe.pool.ntp.org
NTP Pool 0.fedora.pool.ntp.org
NTP Pool 0.freebsd.pool.ntp.org
NTP Pool 0.gentoo.pool.ntp.org
NTP Pool 0.netbsd.pool.ntp.org
NTP Pool 0.openbsd.pool.ntp.org
NTP Pool 0.opensuse.pool.ntp.org
NTP Pool 0.opnsense.pool.ntp.org
NTP Pool 0.pfsense.pool.ntp.org
NTP Pool 0.pool.ntp.org
NTP Pool 0.ru.pool.ntp.org
NTP Pool 0.smartos.pool.ntp.org
NTP Pool 1.amazon.pool.ntp.org
NTP Pool 1.android.pool.ntp.org
NTP Pool 1.arch.pool.ntp.org
NTP Pool 1.asia.pool.ntp.org
NTP Pool 1.askozia.pool.ntp.org
NTP Pool 1.centos.pool.ntp.org
NTP Pool 1.debian.pool.ntp.org
NTP Pool 1.dragonfly.pool.ntp.org
NTP Pool 1.europe.pool.ntp.org
NTP Pool 1.fedora.pool.ntp.org
NTP Pool 1.freebsd.pool.ntp.org
NTP Pool 1.gentoo.pool.ntp.org
NTP Pool 1.netbsd.pool.ntp.org
NTP Pool 1.openbsd.pool.ntp.org
NTP Pool 1.opensuse.pool.ntp.org
NTP Pool 1.opnsense.pool.ntp.org
NTP Pool 1.pfsense.pool.ntp.org
NTP Pool 1.pool.ntp.org
NTP Pool 1.ru.pool.ntp.org
NTP Pool 1.smartos.pool.ntp.org
NTP Pool 2.amazon.pool.ntp.org
NTP Pool 2.android.pool.ntp.org
NTP Pool 2.arch.pool.ntp.org
NTP Pool 2.asia.pool.ntp.org
NTP Pool 2.askozia.pool.ntp.org
NTP Pool 2.centos.pool.ntp.org
NTP Pool 2.debian.pool.ntp.org
NTP Pool 2.dragonfly.pool.ntp.org
NTP Pool 2.europe.pool.ntp.org
NTP Pool 2.fedora.pool.ntp.org
NTP Pool 2.freebsd.pool.ntp.org
NTP Pool 2.gentoo.pool.ntp.org
NTP Pool 2.netbsd.pool.ntp.org
NTP Pool 2.openbsd.pool.ntp.org
NTP Pool 2.opensuse.pool.ntp.org
NTP Pool 2.opnsense.pool.ntp.org
NTP Pool 2.pfsense.pool.ntp.org
NTP Pool 2.pool.ntp.org
NTP Pool 2.ru.pool.ntp.org
NTP Pool 2.smartos.pool.ntp.org
NTP Pool 3.amazon.pool.ntp.org
NTP Pool 3.android.pool.ntp.org
NTP Pool 3.arch.pool.ntp.org
NTP Pool 3.asia.pool.ntp.org
NTP Pool 3.askozia.pool.ntp.org
NTP Pool 3.centos.pool.ntp.org
NTP Pool 3.debian.pool.ntp.org
NTP Pool 3.dragonfly.pool.ntp.org
NTP Pool 3.europe.pool.ntp.org
NTP Pool 3.fedora.pool.ntp.org
NTP Pool 3.freebsd.pool.ntp.org
NTP Pool 3.gentoo.pool.ntp.org
NTP Pool 3.netbsd.pool.ntp.org
NTP Pool 3.openbsd.pool.ntp.org
NTP Pool 3.opensuse.pool.ntp.org
NTP Pool 3.opnsense.pool.ntp.org
NTP Pool 3.pfsense.pool.ntp.org
NTP Pool 3.pool.ntp.org
NTP Pool 3.ru.pool.ntp.org
NTP Pool 3.smartos.pool.ntp.org
NTP Pool asia.pool.ntp.org
NTP Pool europe.pool.ntp.org
NTP Pool pool.ntp.org
NTP Pool ru.pool.ntp.org
NTT x.ns.gin.ntt.net
NTT y.ns.gin.ntt.net
oar navobs1.oar.net
okstate now.okstate.edu
oma ntp1.oma.be
oma ntp2.oma.be
ona ntp1.ona.org
planeacion sesku.planeacion.net
psu otc1.psu.edu
ptb ptbtime1.ptb.de
ptb ptbtime1.ptb.de
ptb ptbtime2.ptb.de
ptb ptbtime2.ptb.de
ptb ptbtime3.ptb.de
QiX NTP ntp.qix.ca
QiX NTP ntp1.qix.ca
QiX NTP ntp2.qix.ca
RIPE ntp.ripe.net
roa hora.roa.es
roa minuto.roa.es
RSU ntp.rsu.edu.ru
shoa ntp.shoa.cl
Stockholm sth1.ntp.se
Stockholm sth2.ntp.se
stratum ntp1.stratum1.ru
stratum ntp2.stratum1.ru
stratum ntp2.stratum2.ru
stratum ntp3.stratum1.ru
stratum ntp3.stratum2.ru
stratum ntp4.stratum1.ru
stratum ntp4.stratum2.ru
stratum ntp5.stratum1.ru
stratum ntp5.stratum2.ru
stupi time1.stupi.se
stygium ntp-ca.stygium.net
Sundsvall svl1.ntp.se
Sundsvall svl2.ntp.se
surfnet chime1.surfnet.nl
symmetricom nist1.symmetricom.com
T-Online ntp1.t-online.de
timegps t2.timegps.net
TimeNL/SIDN Labs ntp.time.nl (ntp1.time.nl)
Trabia time-a.as43289.net
Trabia time-b.as43289.net
Trabia time-c.as43289.net
TRC Fiord ntp.fiord.ru
tu-berlin ntps1-0.cs.tu-berlin.de
tu-berlin ntps1-1.cs.tu-berlin.de
udel mizbeaver.udel.edu
udel rackety.udel.edu
ufe time.ufe.cz
ufl ntp-s1.cise.ufl.edu
ufrj ntps1.pads.ufrj.br
umk ntp.fizyka.umk.pl
uni-erlangen ntps1-0.uni-erlangen.de
uni-erlangen ntps1-1.uni-erlangen.de
uni-stuttgart rustime01.rus.uni-stuttgart.de
uni-stuttgart rustime02.rus.uni-stuttgart.de
University of Saskatchewan tick.usask.ca
University of Saskatchewan tock.usask.ca
uregina clock.uregina.ca
US Navy ntp2.usno.navy.mil
US Navy tick.usno.navy.mil
US Navy tock.usno.navy.mil
usv ntp1.usv.ro
usv ntp3.usv.ro
uu ntp0.nl.uu.net
uu ntp1.nl.uu.net
Versatel ntp1.versatel.net
Versatel ntp2.versatel.net
Versatel time.versatel.de
VNIIFTRI ntp1.niiftri.irkutsk.ru
VNIIFTRI ntp1.vniiftri.ru
VNIIFTRI ntp2.niiftri.irkutsk.ru
VNIIFTRI ntp2.vniiftri.ru
VNIIFTRI ntp21.vniiftri.ru
VNIIFTRI ntp3.vniiftri.ru
VNIIFTRI ntp4.vniiftri.ru
VNIIFTRI vniiftri.khv.ru
VNIIFTRI vniiftri2.khv.ru
vsl ntp.vsl.nl
Web.de ntp.web.de
wustl navobs1.wustl.edu
YYCIX ntp.yycix.ca

Ports

http://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers

Subnet

IPv4

CIDR Subnet Addresses Wildcard
/32 255.255.255.255 1 0.0.0.0
/31 255.255.255.254 2 0.0.0.1
/30 255.255.255.252 4 0.0.0.3
/29 255.255.255.248 8 0.0.0.7
/28 255.255.255.240 16 0.0.0.15
/27 255.255.255.224 32 0.0.0.31
/26 255.255.255.192 64 0.0.0.63
/25 255.255.255.128 128 0.0.0.127
/24 255.255.255.0 256 0.0.0.255
/23 255.255.254.0 512 0.0.1.255
/22 255.255.252.0 1024 0.0.3.255
/21 255.255.248.0 2048 0.0.7.255
/20 255.255.240.0 4096 0.0.15.255
/19 255.255.224.0 8192 0.0.31.255
/18 255.255.192.0 16,384 0.0.63.255
/17 255.255.128.0 32,768 0.0.127.255
/16 255.255.0.0 65,536 0.0.255.255
/15 255.254.0.0 131,072 0.1.255.255
/14 255.252.0.0 262,144 0.3.255.255
/13 255.248.0.0 524,288 0.7.255.255
/12 255.240.0.0 1,048,576 0.15.255.255
/11 255.224.0.0 2,097,152 0.31.255.255
/10 255.192.0.0 4,194,304 0.63.255.255
/9 255.128.0.0 8,388,608 0.127.255.255
/8 255.0.0.0 16,777,216 0.255.255.255

IPv6

Prefix /48 /56 /64 /127 # Addresses
/24 16M 4G 1T 8388608Y 16777216Y
/25 8M 2G 512G 4194304Y 8388608Y
/26 4M 1G 256G 2097152Y 4194304Y
/27 2M 512M 128G 1048576Y 2097152Y
/28 1M 256M 64G 524288Y 1048576Y
/29 512K 128M 32G 262144Y 524288Y
/30 256K 64M 16G 131072Y 262144Y
/31 128K 32M 8G 65536Y 131072Y
/32 64K 16M 4G 32768Y 65536Y
/33 32K 8M 2G 16384Y 32768Y
/34 16K 4M 1G 8192Y 16384Y
/35 8K 2M 512M 4096Y 8192Y
/36 4K 1M 256M 2048Y 4096Y
/37 2K 512K 128M 1024Y 2048Y
/38 1K 256K 64M 512Y 1024Y
/39 512 128K 32M 256Y 512Y
/40 256 64K 16M 128Y 256Y
/41 128 32K 8M 64Y 128Y
/42 64 16K 4M 32Y 64Y
/43 32 8K 2M 16Y 32Y
/44 16 4K 1M 8Y 16Y
/45 8 2K 512K 4Y 8Y
/46 4 1K 256K 2Y 4Y
/47 2 512 128K 1Y 2Y
/48 1 256 64K 512Z 1Y
/49 128 32K 256Z 512Z
/50 64 16K 128Z 256Z
/51 32 8K 64Z 128Z
/52 16 4K 32Z 64Z
/53 8 2K 16Z 32Z
/54 4 1K 8Z 16Z
/55 2 512 4Z 8Z
/56 1 256 2Z 4Z
/57 128 1Z 2Z
/58 64 512E 1Z
/59 32 256E 512E
/60 16 128E 256E
/61 8 64E 128E
/62 4 32E 64E
/63 2 16E 32E
/64 1 8E 16E

IP addresses

The IETF has reserved the address block of 192.0.0.0/24 for use for special purposes relating to protocol assignments. This registry contains the current assignments made by the IETF from this address block. Address prefixes listed in the Special-Purpose Address Registry are not guaranteed routability in any particular local or global context. Source: https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml

Address Block # Name # RFC # Allocation Date # Termination Date #
0.0.0.0/8 "This network" [RFC791], Section 3.2 1981-09 N/A
0.0.0.0/32 "This host on this network" [RFC1122], Section 3.2.1.3 1981-09 N/A
10.0.0.0/8 Private-Use [RFC1918] 1996-02 N/A
100.64.0.0/10 Shared Address Space [RFC6598] 2012-04 N/A
127.0.0.0/8 Loopback [RFC1122], Section 3.2.1.3 1981-09 N/A
169.254.0.0/16 Link Local [RFC3927] 2005-05 N/A
172.16.0.0/12 Private-Use [RFC1918] 1996-02 N/A
192.0.0.0/24 [2] IETF Protocol Assignments [RFC6890], Section 2.1 2010-01 N/A
192.0.0.0/29 IPv4 Service Continuity Prefix [RFC7335] 2011-06 N/A
192.0.0.8/32 IPv4 dummy address [RFC7600] 2015-03 N/A
192.0.0.9/32 Port Control Protocol Anycast [RFC7723] 2015-10 N/A
192.0.0.10/32 Traversal Using Relays around NAT Anycast [RFC8155] 2017-02 N/A
192.0.0.170/32, 192.0.0.171/32 NAT64/DNS64 Discovery [RFC8880][RFC7050], Section 2.2 2013-02 N/A
192.0.2.0/24 Documentation (TEST-NET-1) [RFC5737] 2010-01 N/A
192.31.196.0/24 AS112-v4 [RFC7535] 2014-12 N/A
192.52.193.0/24 AMT [RFC7450] 2014-12 N/A
192.88.99.0/24 Deprecated (6to4 Relay Anycast) [RFC7526] 2001-06 2015-03
192.168.0.0/16 Private-Use [RFC1918] 1996-02 N/A
192.175.48.0/24 Direct Delegation AS112 Service [RFC7534] 1996-01 N/A
198.18.0.0/15 Benchmarking [RFC2544] 1999-03 N/A
198.51.100.0/24 Documentation (TEST-NET-2) [RFC5737] 2010-01 N/A
203.0.113.0/24 Documentation (TEST-NET-3) [RFC5737] 2010-01 N/A
240.0.0.0/4 Reserved [RFC1112], Section 4 1989-08 N/A
255.255.255.255/32 Limited Broadcast [RFC8190] [RFC919], Section 7 1984-10 N/A

Further, useful lists:

IPv4 possible notations

All possible notations of the IPv4 address 8.8.8.8 (source)

  • 8.8.8.8
  • 134744072
  • 0x8080808
  • 01002004010
  • 8.526344
  • 8.0x80808
  • 8.02004010
  • 8.8.2056
  • 8.8.0x808
  • 8.8.04010
  • 8.8.8.0x8
  • 8.8.8.010
  • 8.8.0x8.8
  • 8.8.0x8.0x8
  • 8.8.0x8.010
  • 8.8.010.8
  • 8.8.010.0x8
  • 8.8.010.010
  • 8.0x8.2056
  • 8.0x8.0x808
  • 8.0x8.04010
  • 8.0x8.8.8
  • 8.0x8.8.0x8
  • 8.0x8.8.010
  • 8.0x8.0x8.8
  • 8.0x8.0x8.0x8
  • 8.0x8.0x8.010
  • 8.0x8.010.8
  • 8.0x8.010.0x8
  • 8.0x8.010.010
  • 8.010.2056
  • 8.010.0x808
  • 8.010.04010
  • 8.010.8.8
  • 8.010.8.0x8
  • 8.010.8.010
  • 8.010.0x8.8
  • 8.010.0x8.0x8
  • 8.010.0x8.010
  • 8.010.010.8
  • 8.010.010.0x8
  • 8.010.010.010
  • 0x8.526344
  • 0x8.0x80808
  • 0x8.02004010
  • 0x8.8.2056
  • 0x8.8.0x808
  • 0x8.8.04010
  • 0x8.8.8.8
  • 0x8.8.8.0x8
  • 0x8.8.8.010
  • 0x8.8.0x8.8
  • 0x8.8.0x8.0x8
  • 0x8.8.0x8.010
  • 0x8.8.010.8
  • 0x8.8.010.0x8
  • 0x8.8.010.010
  • 0x8.0x8.2056
  • 0x8.0x8.0x808
  • 0x8.0x8.04010
  • 0x8.0x8.8.8
  • 0x8.0x8.8.0x8
  • 0x8.0x8.8.010
  • 0x8.0x8.0x8.8
  • 0x8.0x8.0x8.0x8
  • 0x8.0x8.0x8.010
  • 0x8.0x8.010.8
  • 0x8.0x8.010.0x8
  • 0x8.0x8.010.010
  • 0x8.010.2056
  • 0x8.010.0x808
  • 0x8.010.04010
  • 0x8.010.8.8
  • 0x8.010.8.0x8
  • 0x8.010.8.010
  • 0x8.010.0x8.8
  • 0x8.010.0x8.0x8
  • 0x8.010.0x8.010
  • 0x8.010.010.8
  • 0x8.010.010.0x8
  • 0x8.010.010.010
  • 010.526344
  • 010.0x80808
  • 010.02004010
  • 010.8.2056
  • 010.8.0x808
  • 010.8.04010
  • 010.8.8.8
  • 010.8.8.0x8
  • 010.8.8.010
  • 010.8.0x8.8
  • 010.8.0x8.0x8
  • 010.8.0x8.010
  • 010.8.010.8
  • 010.8.010.0x8
  • 010.8.010.010
  • 010.0x8.2056
  • 010.0x8.0x808
  • 010.0x8.04010
  • 010.0x8.8.8
  • 010.0x8.8.0x8
  • 010.0x8.8.010
  • 010.0x8.0x8.8
  • 010.0x8.0x8.0x8
  • 010.0x8.0x8.010
  • 010.0x8.010.8
  • 010.0x8.010.0x8
  • 010.0x8.010.010
  • 010.010.2056
  • 010.010.0x808
  • 010.010.04010
  • 010.010.8.8
  • 010.010.8.0x8
  • 010.010.8.010
  • 010.010.0x8.8
  • 010.010.0x8.0x8
  • 010.010.0x8.010
  • 010.010.010.8
  • 010.010.010.0x8
  • 010.010.010.010

TTL as OS identifier

There is a chance to guess the OS based on its TTL.

Here is an overview:

OS Version Protocol TTL
*nix (Linux/Unix) 64
AIX 3.2, 4.1 ICMP 255
AIX TCP 60
AIX UDP 30
BSDI BSD/OS 3.1 and 4.0 ICMP 255
Cisco ICMP 254
Compa Tru64 v5.0 ICMP 64
DEC Pathworks V5 TCP and UDP 30
Foundry ICMP 64
FreeBSD 5 ICMP 64
FreeBSD 3.4, 4.0 ICMP 255
FreeBSD 2.1R TCP and UDP 64
HP-UX 9.0x TCP and UDP 30
HP-UX 11 ICMP 255
HP-UX 11 TCP 64
HP-UX 10.2 ICMP 255
HP-UX 10.01 TCP and UDP 64
Irix 6.x TCP and UDP 60
Irix 6.5.3, 6.5.8 ICMP 255
Irix 5.3 TCP and UDP 60
Linux Red Hat 9 ICMP and TCP 64
Linux 2.4 kernel ICMP 255
Linux 2.2.14 kernel ICMP 255
Linux 2.0.x kernel ICMP 64
MPE/IX (HP) ICMP 200
MacOS/MacTCP X (10.5.6) ICMP/TCP/UDP 64
MacOS/MacTCP 2.0.x TCP and UDP 60
NetBSD ICMP 255
Netgear FVG318 ICMP and UDP 64
OS/2 TCP/IP 3.0 64
OSF/1 V3.2A TCP 60
OSF/1 V3.2A UDP 30
OpenBSD 2.6 & 2.7 ICMP 255
OpenVMS 07.01.2002 ICMP 255
Solaris 2.8 TCP 64
Solaris 2.5.1, 2.6, 2.7, 2.8 ICMP 255
Solaris/AIX 254
Stratus TCP_OS (14.3+) TCP and UDP 64
Stratus TCP_OS (14.2-) TCP and UDP 30
Stratus TCP_OS ICMP 255
Stratus STCP ICMP/TCP/UDP 60
SunOS 5.7 ICMP and TCP 255
SunOS 4.1.3/4.1.4 TCP and UDP 60
Ultrix V4.2 – 4.5 ICMP 255
Ultrix V4.1/V4.2A TCP 60
Ultrix V4.1/V4.2A UDP 30
VMS/Multinet TCP and UDP 64
VMS/TCPware TCP 60
VMS/TCPware UDP 64
VMS/UCX TCP and UDP 128
VMS/Wollongong 1.1.1.1 TCP 128
VMS/Wollongong 1.1.1.1 UDP 30
Windows for Workgroups TCP and UDP 32
Windows XP ICMP/TCP/UDP 128
Windows Vista ICMP/TCP/UDP 128
Windows Server 2008 ICMP/TCP/UDP 128
Windows Server 2003 128
Windows NT 4.0 SP6+ 128
Windows NT 4.0 SP5- 32
Windows NT 4.0 TCP and UDP 128
Windows NT 4 WRKS SP 3, SP 6a ICMP 128
Windows NT 4 Server SP4 ICMP 128
Windows NT 3.51 TCP and UDP 32
Windows ME ICMP 128
Windows 98, 98 SE ICMP 128
Windows 98 ICMP 32
Windows 98 TCP 128
Windows 95 TCP and UDP 32
Windows 7 ICMP/TCP/UDP 128
Windows 2000 pro ICMP/TCP/UDP 128
Windows 2000 family ICMP 128
Windows 10 ICMP/TCP/UDP 128
Windows 128
juniper ICMP 64

TCP Fingerprints

A TCP fingerprint is a set of low-level TCP option values and patterns that, when combined, can reveal what kind of system is connecting—even before any higher-level protocol (like HTTP or TLS) is exchanged. Here are some examples:

# Field/Option Typical Values / Patterns What It Usually Indicates
1 MSS (Maximum Segment Size) 1460, 1380, 1440, 536 1460: Ethernet (Linux/Windows/Mac), 1380: VPNs, 536: legacy systems or special networks
2 Window Scale 2, 4, 8, 256, 512 8: Linux default, 2/4: Windows, other: rare/custom stacks
3 SACK Permitted Present/Absent Present: Modern OS, Absent: some old stacks or IoT devices
4 Timestamps Option Present/Absent Present: Linux/Mac default, Absent: Windows, or sometimes due to NAT/routers
5 ECN (Explicit Congestion Notif.) Enabled/Disabled Enabled: Modern Linux/Chrome, Disabled: many Windows/Mac
6 Window Size 65535, 5840, 64240, 29200 65535: Windows, 5840: Linux, 29200: MacOS
7 TTL (Time To Live) 64, 128, 255 64: Linux/Mac, 128: Windows, 255: BSD/Networking appliances
8 IP Version 4, 6 IPv4: Default everywhere, IPv6: Modern/advanced users
9 Source Port Range 49152-65535 (Linux), 1025-5000 (Windows pre-2008) Linux/Unix: High ephemeral, Old Windows: Low ephemeral
10 TCP Option Ordering MSS, SACK, Timestamp, WS The order is surprisingly unique per OS/stack
11 TLS Version (if HTTPS) 1.2, 1.3 1.3: Newer clients (Chrome/Firefox), 1.2: Still common, older clients
12 Cipher Suites in TLS Varies by browser/app Can often distinguish between Chrome, Firefox, curl, bots, etc.
13 TLS Extensions Supported Groups, ALPN, SNI Presence/order helps identify browser/app/version