`21.com`

DNSSEC	⚠️ Not signed
A	2606:4700::6812:14e1^{🇺🇸 Cloudflare2606:4700::/44 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
A	2606:4700::6812:15e1^{🇺🇸 Cloudflare2606:4700::/44 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
A	104.18.20.225^{Cloudflare104.18.16.0/20 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
A	104.18.21.225^{Cloudflare104.18.16.0/20 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
NS	`clint.ns.cloudflare.com` ⭐
		A	2606:4700:58::adf5:3b5a^{🇺🇸 Cloudflare2606:4700:50::/44 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`clint.ns.cloudflare.com`
		A	2803:f800:50::6ca2:c15a^{🇨🇷 Cloudflare2803:f800:50::/45 LACNIC generated route6 for CloudFlare Latin America S.R.L}
			PTR	`clint.ns.cloudflare.com`
		A	2a06:98c1:50::ac40:215a^{🇺🇸 Cloudflare2a06:98c1:50::/45}
			PTR	`clint.ns.cloudflare.com`
		A	108.162.193.90^{🇺🇸 Cloudflare108.162.193.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`clint.ns.cloudflare.com`
		A	172.64.33.90^{🇺🇸 Cloudflare172.64.33.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`clint.ns.cloudflare.com`
		A	173.245.59.90^{🇺🇸 Cloudflare173.245.59.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`clint.ns.cloudflare.com`
NS	`serenity.ns.cloudflare.com`
		A	2606:4700:50::a29f:266c^{🇺🇸 Cloudflare2606:4700:50::/44 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`serenity.ns.cloudflare.com`
		A	2803:f800:50::6ca2:c26c^{🇨🇷 Cloudflare2803:f800:50::/45 LACNIC generated route6 for CloudFlare Latin America S.R.L}
			PTR	`serenity.ns.cloudflare.com`
		A	2a06:98c1:50::ac40:226c^{🇺🇸 Cloudflare2a06:98c1:50::/45}
			PTR	`serenity.ns.cloudflare.com`
		A	108.162.194.108^{🇺🇸 Cloudflare108.162.194.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`serenity.ns.cloudflare.com`
		A	162.159.38.108^{Cloudflare162.159.32.0/20 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`serenity.ns.cloudflare.com`
		A	172.64.34.108^{🇺🇸 Cloudflare172.64.34.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`serenity.ns.cloudflare.com`
MX	`smtp.google.com` ⭐
		A	2607:f8b0:4023:c03::1a^{🇺🇸 Google2607:f8b0::/32}
			PTR	`dy-in-f26.1e100.net`
		A	2607:f8b0:4023:c03::1b^{🇺🇸 Google2607:f8b0::/32}
			PTR	`dy-in-f27.1e100.net`
		A	2607:f8b0:4023:c0d::1a^{🇺🇸 Google2607:f8b0::/32}
			PTR	`dl-in-f26.1e100.net`
		A	2607:f8b0:4023:c0d::1b^{🇺🇸 Google2607:f8b0::/32}
			PTR	`dl-in-f27.1e100.net`
		A	74.125.137.26^{🇺🇸 Google74.125.137.0/24}
			PTR	`dy-in-f26.1e100.net`
		A	74.125.137.27^{🇺🇸 Google74.125.137.0/24}
			PTR	`dy-in-f27.1e100.net`
		A	142.250.101.26^{🇺🇸 Google142.250.101.0/24}
			PTR	`dz-in-f26.1e100.net`
		A	142.251.2.26^{🇺🇸 Google142.251.2.0/24}
			PTR	`dl-in-f26.1e100.net`
		A	142.251.2.27^{🇺🇸 Google142.251.2.0/24}
			PTR	`dl-in-f27.1e100.net`
TXT	`google-gws-recovery-domain-verification=70219444`
TXT	`google-site-verification=5S_-UwATOVTK3sa2wiZtqNS4917T0mX3-gINqG4SUPs`
TXT	`google-site-verification=IWS1OYnROYff2a_w9tUmJWv_tM85qOGVkio314Dcbdk`
TXT	`google-site-verification=wkutgY6KGuD8zt5RXmqbTeMvX0HK9DRA2oYsfENpx_M`
TXT	`v=spf1 include:_spf.mx.cloudflare.net include:_spf.21_com._d.easydmarc.pro ~all`
HTTPS	HTTP/2 ✓ hints match
		IPv4 hints	104.18.20.225, 104.18.21.225
		IPv6 hints	2606:4700::6812:14e1, 2606:4700::6812:15e1
SOA	`clint.ns.cloudflare.com`dns@cloudflare.com serial=2402420755

`com`

	DNSSEC	🔒 Signed (DS record present)
	NS	`a.gtld-servers.net` ⭐
	NS	`b.gtld-servers.net`
	NS	`c.gtld-servers.net`
	NS	`d.gtld-servers.net`
	NS	`e.gtld-servers.net`
	NS	`f.gtld-servers.net`
	NS	`g.gtld-servers.net`
	NS	`h.gtld-servers.net`
	NS	`i.gtld-servers.net`
	NS	`j.gtld-servers.net`
	NS	`k.gtld-servers.net`
	NS	`l.gtld-servers.net`
	NS	`m.gtld-servers.net`
	SOA	`a.gtld-servers.net`nstld@verisign-grs.com serial=1776943917

rank #289058 globally
rank #122268 in the tld
WOT: UNKNOWN (70/100)
📈 Tranco rank: #719,822

Subdomains

www.21.com

Same first word

21.(0x787878)

21.ink

21.pictures

21.show

21.nl

21.agency

21.co

21.biz

21.lv

21.uk

21.ru

21.co.za

21.co.tz

21.finance

21.re

21.co.com

21.ax

21.nu

21.business

21.casino

21.red

21.pl

21.ee

21.com.vn

21.partners

21.to

21.ie

21.photos

21.sb

21.cc

21.city

21.gs

21.fr

21.live

21.by

21.com.es

21.net.cn

21.eu

21.run

21.pw

21.se

21.org.cn

21.chat

21.net

21.game

21.la

21.ag

21.diamonds

21.cn

21.de

21.training

21.ca

21.org

21.com.tw

21.co.uk

21.vc

21.am

21.im

21.rs

21.amsterdam

21.com

21.bet

21.center

21.kz

21.fyi

21.cm

21.web.app

21.su

21.network

21.si

21.ph

21.is

21.be

21.com.ua

21.pe

21.edu.ar

21.gg

21.technology

21.capital

21.dk

21.email

21.ai

21.wf

21.sk

21.zone

21.immo

21.hk

21.cz

21.academy

21.style

21.school

Similar names

12.de

12.co.kr

12.in-addr.arpa

12.ag

12.kz

12.ie

12.plus

12.com.ua

12.cz

12.eu

12.uk

12.sg

12.life

12.network

12.dk

12.com.cn

12.org.ru

12.cx

12.org

12.nu

12.gl

12.vip

12.net.cn

12.gr

12.fyi

12.ai

12.tt

12.hk

12.gs

12.amsterdam

12.fr

12.vc

12.am

12.agency

12.digital

12.ac.cn

12.com.vn

12.lt

12.si

12.cfd

12.tf

12.pw

12.be

12.fi

12.cc

12.is

12.chat

12.netlify.app

12.app

12.solutions

12.dyndns.tv

DNS History

51 records (7 active, 44 former)

○NSaarav.ns.cloudflare.com2021-10-24 → 2021-10-24 · 4 obs

○ 2020-10-13 01:55:12
● 2021-10-24 02:17:58
○ 2026-02-16 02:14:16
○ 2026-04-23 11:35:56

●NSclint.ns.cloudflare.com2026-02-16 → 2026-04-23 · 3 obs

○ 2021-10-24 02:17:58
● 2026-02-16 02:14:16
● 2026-04-23 11:35:56

○NSdns1.name-services.com2015-08-08 → 2015-09-04 · 4 obs

● 2015-08-08 03:51:12
● 2015-09-04 22:26:54
○ 2015-09-21 08:22:42
○ 2026-04-23 11:35:56

○NSdns1.safenames.com2020-10-13 → 2020-10-13 · 4 obs

○ 2017-11-03 17:24:26
● 2020-10-13 01:55:12
○ 2021-10-24 02:17:58
○ 2026-04-23 11:35:56

○NSdns2.name-services.com2015-08-08 → 2015-09-04 · 4 obs

● 2015-08-08 03:51:12
● 2015-09-04 22:26:54
○ 2015-09-21 08:22:42
○ 2026-04-23 11:35:56

○NSdns2.safenames.net2020-10-13 → 2020-10-13 · 4 obs

○ 2017-11-03 17:24:26
● 2020-10-13 01:55:12
○ 2021-10-24 02:17:58
○ 2026-04-23 11:35:56

○NSdns3.name-services.com2015-08-08 → 2015-09-04 · 4 obs

● 2015-08-08 03:51:12
● 2015-09-04 22:26:54
○ 2015-09-21 08:22:42
○ 2026-04-23 11:35:56

○NSdns3.safenames.org2020-10-13 → 2020-10-13 · 4 obs

○ 2017-11-03 17:24:26
● 2020-10-13 01:55:12
○ 2021-10-24 02:17:58
○ 2026-04-23 11:35:56

○NSdns4.name-services.com2015-08-08 → 2015-09-04 · 4 obs

● 2015-08-08 03:51:12
● 2015-09-04 22:26:54
○ 2015-09-21 08:22:42
○ 2026-04-23 11:35:56

○NSdns5.name-services.com2015-08-08 → 2015-09-04 · 4 obs

● 2015-08-08 03:51:12
● 2015-09-04 22:26:54
○ 2015-09-21 08:22:42
○ 2026-04-23 11:35:56

○NSjen.ns.cloudflare.com2021-10-24 → 2021-10-24 · 4 obs

○ 2020-10-13 01:55:12
● 2021-10-24 02:17:58
○ 2026-02-16 02:14:16
○ 2026-04-23 11:35:56

○NSns.myhosting.com2016-07-09 → 2017-11-03 · 5 obs

○ 2016-05-13 16:39:22
● 2016-07-09 08:35:04
● 2017-11-03 17:24:26
○ 2020-10-13 01:55:12
○ 2026-04-23 11:35:56

○NSns1.myhosting.com2016-07-09 → 2017-11-03 · 5 obs

○ 2016-05-13 16:39:22
● 2016-07-09 08:35:04
● 2017-11-03 17:24:26
○ 2020-10-13 01:55:12
○ 2026-04-23 11:35:56

○NSns2.myhosting.com2016-07-09 → 2017-11-03 · 5 obs

○ 2016-05-13 16:39:22
● 2016-07-09 08:35:04
● 2017-11-03 17:24:26
○ 2020-10-13 01:55:12
○ 2026-04-23 11:35:56

●NSserenity.ns.cloudflare.com2026-02-16 → 2026-04-23 · 3 obs

○ 2021-10-24 02:17:58
● 2026-02-16 02:14:16
● 2026-04-23 11:35:56

○NSwww.21.com2015-09-21 → 2016-05-13 · 5 obs

○ 2015-09-04 22:26:54
● 2015-09-21 08:22:42
● 2016-05-13 16:39:22
○ 2016-07-09 08:35:04
○ 2026-04-23 11:35:56

○MXalt1.aspmx.l.google.com2020-10-13 → 2021-10-24 · 5 obs

○ 2017-11-03 17:24:26
● 2020-10-13 01:55:12
● 2021-10-24 02:17:58
○ 2026-02-16 02:14:16
○ 2026-04-23 11:35:56

○MXalt2.aspmx.l.google.com2020-10-13 → 2021-10-24 · 5 obs

○ 2017-11-03 17:24:26
● 2020-10-13 01:55:12
● 2021-10-24 02:17:58
○ 2026-02-16 02:14:16
○ 2026-04-23 11:35:56

○MXalt3.aspmx.l.google.com2020-10-13 → 2021-10-24 · 5 obs

○ 2017-11-03 17:24:26
● 2020-10-13 01:55:12
● 2021-10-24 02:17:58
○ 2026-02-16 02:14:16
○ 2026-04-23 11:35:56

○MXalt4.aspmx.l.google.com2020-10-13 → 2021-10-24 · 5 obs

○ 2017-11-03 17:24:26
● 2020-10-13 01:55:12
● 2021-10-24 02:17:58
○ 2026-02-16 02:14:16
○ 2026-04-23 11:35:56

○MXaspmx.l.google.com2020-10-13 → 2021-10-24 · 5 obs

○ 2017-11-03 17:24:26
● 2020-10-13 01:55:12
● 2021-10-24 02:17:58
○ 2026-02-16 02:14:16
○ 2026-04-23 11:35:56

○MXio.bouncemx.com2015-09-21 → 2016-05-13 · 5 obs

○ 2015-09-04 22:26:54
● 2015-09-21 08:22:42
● 2016-05-13 16:39:22
○ 2016-07-09 08:35:04
○ 2026-04-23 11:35:56

○MXmx.spamexperts.com2016-07-09 → 2017-11-03 · 5 obs

○ 2016-05-13 16:39:22
● 2016-07-09 08:35:04
● 2017-11-03 17:24:26
○ 2020-10-13 01:55:12
○ 2026-04-23 11:35:56

○MXp.nsm.ctmail.com2015-08-08 → 2015-09-04 · 4 obs

● 2015-08-08 03:51:12
● 2015-09-04 22:26:54
○ 2015-09-21 08:22:42
○ 2026-04-23 11:35:56

○MXroute1.mx.cloudflare.net2026-02-16 → 2026-04-18 · 5 obs

○ 2021-10-24 02:17:58
● 2026-02-16 02:14:16
● 2026-04-18 10:35:44
○ 2026-04-19 13:54:12
○ 2026-04-23 11:35:56

○MXroute2.mx.cloudflare.net2026-02-16 → 2026-04-18 · 5 obs

○ 2021-10-24 02:17:58
● 2026-02-16 02:14:16
● 2026-04-18 10:35:44
○ 2026-04-19 13:54:12
○ 2026-04-23 11:35:56

○MXroute3.mx.cloudflare.net2026-02-16 → 2026-04-18 · 5 obs

○ 2021-10-24 02:17:58
● 2026-02-16 02:14:16
● 2026-04-18 10:35:44
○ 2026-04-19 13:54:12
○ 2026-04-23 11:35:56

●MXsmtp.google.com2026-04-19 → 2026-04-23 · 3 obs

○ 2026-04-18 10:35:44
● 2026-04-19 13:54:12
● 2026-04-23 11:35:56

●A104.18.20.2252026-02-16 → 2026-04-23 · 3 obs

○ 2021-10-24 02:17:58
● 2026-02-16 02:14:16
● 2026-04-23 11:35:56

●A104.18.21.2252026-02-16 → 2026-04-23 · 3 obs

○ 2021-10-24 02:17:58
● 2026-02-16 02:14:16
● 2026-04-23 11:35:56

○A104.22.6.1532021-10-24 → 2021-10-24 · 4 obs

○ 2020-10-13 01:55:12
● 2021-10-24 02:17:58
○ 2026-02-16 02:14:16
○ 2026-04-23 11:35:56

○A104.22.7.1532021-10-24 → 2021-10-24 · 4 obs

○ 2020-10-13 01:55:12
● 2021-10-24 02:17:58
○ 2026-02-16 02:14:16
○ 2026-04-23 11:35:56

○A159.100.24.1452020-10-13 → 2020-10-13 · 4 obs

○ 2017-11-03 17:24:26
● 2020-10-13 01:55:12
○ 2021-10-24 02:17:58
○ 2026-04-23 11:35:56

○A168.144.109.152016-07-09 → 2017-11-03 · 5 obs

○ 2016-05-13 16:39:22
● 2016-07-09 08:35:04
● 2017-11-03 17:24:26
○ 2020-10-13 01:55:12
○ 2026-04-23 11:35:56

○A172.67.21.402021-10-24 → 2021-10-24 · 4 obs

○ 2020-10-13 01:55:12
● 2021-10-24 02:17:58
○ 2026-02-16 02:14:16
○ 2026-04-23 11:35:56

●A2606:4700::6812:14e12026-02-16 → 2026-04-23 · 3 obs

○ 2021-10-24 02:17:58
● 2026-02-16 02:14:16
● 2026-04-23 11:35:56

●A2606:4700::6812:15e12026-02-16 → 2026-04-23 · 3 obs

○ 2021-10-24 02:17:58
● 2026-02-16 02:14:16
● 2026-04-23 11:35:56

○A2606:4700:10::6816:6992021-10-24 → 2021-10-24 · 4 obs

○ 2020-10-13 01:55:12
● 2021-10-24 02:17:58
○ 2026-02-16 02:14:16
○ 2026-04-23 11:35:56

○A2606:4700:10::6816:7992021-10-24 → 2021-10-24 · 4 obs

○ 2020-10-13 01:55:12
● 2021-10-24 02:17:58
○ 2026-02-16 02:14:16
○ 2026-04-23 11:35:56

○A2606:4700:10::ac43:15282021-10-24 → 2021-10-24 · 4 obs

○ 2020-10-13 01:55:12
● 2021-10-24 02:17:58
○ 2026-02-16 02:14:16
○ 2026-04-23 11:35:56

○A69.64.147.2432015-08-08 → 2015-09-04 · 4 obs

● 2015-08-08 03:51:12
● 2015-09-04 22:26:54
○ 2015-09-21 08:22:42
○ 2026-04-23 11:35:56

○A70.39.84.2272015-09-23 → 2015-09-23 · 4 obs

○ 2015-09-21 08:22:42
● 2015-09-23 21:43:18
○ 2015-10-08 13:33:00
○ 2026-04-23 11:35:56

○A70.39.84.2282015-12-31 → 2015-12-31 · 4 obs

○ 2015-12-08 13:32:56
● 2015-12-31 07:52:42
○ 2016-01-12 02:26:48
○ 2026-04-23 11:35:56

○A70.39.84.2312016-01-12 → 2016-01-12 · 4 obs

○ 2015-12-31 07:52:42
● 2016-01-12 02:26:48
○ 2016-02-03 01:21:44
○ 2026-04-23 11:35:56

○A70.39.84.2332015-10-08 → 2016-03-19 · 7 obs

○ 2015-09-23 21:43:18
● 2015-10-08 13:33:00
○ 2015-10-25 15:44:18
○ 2016-02-03 01:21:44
● 2016-03-19 22:48:52
○ 2016-04-23 10:42:18
○ 2026-04-23 11:35:56

○A70.39.84.2372015-12-08 → 2015-12-08 · 4 obs

○ 2015-10-25 15:44:18
● 2015-12-08 13:32:56
○ 2015-12-31 07:52:42
○ 2026-04-23 11:35:56

○A70.39.84.2382016-02-03 → 2016-02-03 · 4 obs

○ 2016-01-12 02:26:48
● 2016-02-03 01:21:44
○ 2016-03-19 22:48:52
○ 2026-04-23 11:35:56

○A70.39.84.2402015-09-21 → 2015-09-21 · 4 obs

○ 2015-09-04 22:26:54
● 2015-09-21 08:22:42
○ 2015-09-23 21:43:18
○ 2026-04-23 11:35:56

○A70.39.84.2412015-10-25 → 2015-10-25 · 4 obs

○ 2015-10-08 13:33:00
● 2015-10-25 15:44:18
○ 2015-12-08 13:32:56
○ 2026-04-23 11:35:56

○A70.39.84.2422016-04-23 → 2016-05-13 · 5 obs

○ 2016-03-19 22:48:52
● 2016-04-23 10:42:18
● 2016-05-13 16:39:22
○ 2016-07-09 08:35:04
○ 2026-04-23 11:35:56

○CNAMEnum2.dcoin.co2015-09-21 → 2016-05-13 · 4 obs

● 2015-09-21 08:22:42
● 2016-05-13 16:39:22
○ 2016-07-09 08:35:04
○ 2026-04-23 11:35:56

🔍 DNS Trace

📋 Delegation Chain

Zone	Nameservers	Glue
com	l.gtld-servers.net, j.gtld-servers.net, h.gtld-servers.net, d.gtld-servers.net...	-
21.com	clint.ns.cloudflare.com, serenity.ns.cloudflare.com	12 records

✅ Authoritative Response

Server:108.162.194.108

NS records: clint.ns.cloudflare.com, serenity.ns.cloudflare.com

🔒 DNSSEC Status

⚠️ Insecure (no DNSSEC)

No DS record for 21.com (unsigned zone)

⏱️ Timing

Total: 221ms | Queries: -

📄 Records

Type	Count	Sample Data
A	2	`104.18.20.225, 104.18.21.225`
AAAA	2	`2606:4700::6812:15e1, 2606:4700::6812:14e1`
NS	2	`clint.ns.cloudflare.com, serenity.ns.cloudflare.com`
MX	1	`smtp.google.com (pri: 1)`
TXT	5	`google-gws-recovery-domain-verification=, google-site-verification=5S_-UwATOVTK3sa...`
HTTPS	1	`{"priority":1,"target":".","alpn":["h2"]`
SOA	1	`clint.ns.cloudflare.com dns.cloudflare.c`

📌 Glue Records Collected

Total: 12

Out-of-bailiwick: 12 (clint.ns.cloudflare.com, clint.ns.cloudflare.com, clint.ns.cloudflare.com...)

Analysis

Hierarchy

21.com is a parent of www.21.com.

IP Addresses

21.com points to four IP numbers: 2606:4700::6812:14e1, 2606:4700::6812:15e1, 104.18.20.225 and 104.18.21.225.

Other host names, for instance feldschloesschen.swiss, www.webmvr.com, ninja.new, www.allstar.gg.cdn.cloudflare.net and michaelhill.co.nz share IP numbers with 21.com.

Name Servers

Delegation for 21.com rests with two name servers, clint.ns.cloudflare.com and serenity.ns.cloudflare.com.

21.com shares the same name server setup as other domains, including raag.org.tw, tpdc.org.tw, hcid.org.tw, sle.org.tw and tmica.org.tw.

21.com at least partially shares name servers with other domains, for instance 43688.biz, donaugustocigars.us, collectablesmall.com, vaporinspire.com and kuimaicn.com.

These name servers are commonly used with the name servers wally.ns.cloudflare.com.

Host names with six IP numbers: clint.ns.cloudflare.com points to: 2606:4700:58::adf5:3b5a, 2803:f800:50::6ca2:c15a, 2a06:98c1:50::ac40:215a, 108.162.193.90, 172.64.33.90 and 173.245.59.90. serenity.ns.cloudflare.com points to: 2606:4700:50::a29f:266c, 2803:f800:50::6ca2:c26c, 2a06:98c1:50::ac40:226c, 108.162.194.108, 162.159.38.108 and 172.64.34.108.

Mail Servers

21.com is handled by a single mail server, smtp.google.com.

21.com uses the same mail server configuration as other domains, such as sudafarm.com, a2dps.com.br, spelitestaysllc.com, chopraoffice.com and lonepc.com.

21.com shares mail servers with other domains at least in part, for instance boxtronics.com, grupoeducare.com, tecoman.net, alluxio.com and vecoro.com.

These mail servers are often used with alt1.aspmx.l.google.com, alt2.aspmx.l.google.com, aspmx.l.google.com, alt3.aspmx.l.google.com and alt4.aspmx.l.google.com.

Host smtp.google.com points to nine IP numbers: 2607:f8b0:4023:c03::1a, 2607:f8b0:4023:c03::1b, 2607:f8b0:4023:c0d::1a, 2607:f8b0:4023:c0d::1b, 74.125.137.26, 74.125.137.27, 142.250.101.26, 142.251.2.26 and 142.251.2.27.

21.com - robtex.com

21.com

com

Subdomains

Same first word

Similar names

DNS History

🔍 DNS Trace

📋 Delegation Chain

✅ Authoritative Response

🔒 DNSSEC Status

⏱️ Timing

📄 Records

📌 Glue Records Collected

Analysis

Hierarchy

IP Addresses

Name Servers

Mail Servers

`21.com`

`com`