`proxy-out-a.booking.com`

	DNSSEC	⚠️ Not signed
	A	5.57.21.129^{🇳🇱 Booking-BV5.57.21.0/24}

`booking.com`

	DNSSEC	⚠️ Not signed
	A	3.170.42.19^{🇺🇸 Amazon3.170.40.0/22}
	A	3.170.42.86^{🇺🇸 Amazon3.170.40.0/22}
	A	3.170.42.87^{🇺🇸 Amazon3.170.40.0/22}
	A	3.170.42.127^{🇺🇸 Amazon3.170.40.0/22}
	NS	`ns-1288.awsdns-33.org` ⭐
	NS	`ns-1959.awsdns-52.co.uk`
	NS	`ns-508.awsdns-63.com`
	NS	`ns-716.awsdns-25.net`
	MX	`mxa-0032a201.gslb.pphosted.com` ⭐
	MX	`mxb-0032a201.gslb.pphosted.com` ⭐
	TXT	`Dynatrace-site-verification=3a88fc1a-195c-455d-ab87-88d09191496b__drhtlct978b...`
	TXT	`MS=ms35392088`
	TXT	`MS=ms94636132`
	TXT	`VkJHqtn1JPDHrgqwzb8C30fmoABFhxVfjIOtLvlUK06CUwKgd2mevDGtnDhWZcNbxEgK39DOezbHa...`
	TXT	`ZOOM_verify_rRPrFA9oTH2bxfFkJeQTzA`
	TXT	`_14w4c7x8j3wh3rcjq506pc8tpni5e0j`
	TXT	`_globalsign-domain-verification=9Xqu2bonefjuoUF-XmyjAptAfuE-yStJz6wy9UnH-C`
	TXT	`_globalsign-domain-verification=FSlSaYMuHsffF-JRsSpJSonQOV0_jwrwl5kQGpFdtb`
	TXT	`_globalsign-domain-verification=l_BNpBAnk-rKZRyXJ9UkBfv9o6EEuuenkBrGpYNYo0`
	TXT	`_ngvwjw7ivb5mv4iz4ynfsao26826rul`
	TXT	`_t33b2jwn9aya9tjjl23glp3pdv3puct`
	TXT	`adobe-idp-site-verification=040db58f-cfb9-4203-a555-bfcd15b24b86`
	TXT	`anthropic-domain-verification-3tn1j6=kp9CbC14s2pKcVhSOOlbHwQHz`
	TXT	`apple-domain-verification=immERz8LzjEgeSoW`
	TXT	`asv=93db973d8bc6fd37d0c9e0c3feebff95`
	TXT	`atlassian-domain-verification=F3hugs/a4ZZHwjGTLmlb12IMA3TIRiz3ifqw4TKRz9tWk0L...`
	TXT	`atlassian-domain-verification=PEQekniknkTLbMzMw6Ifb9G9YWzhgcGHzIne34xYo7zW9/r...`
	TXT	`atlassian-sending-domain-verification=e6842471-4159-4738-b15a-cefe813dc42a`
	TXT	`canva-site-verification=KAuoIY0y5F95ChkJB52A2w`
	TXT	`cisco-ci-domain-verification=45d8573a6620606f09d1556681408112c9f9754309b02423...`
	TXT	`cursor-domain-verification-wv67f5=cvoPd4JZECcPi6V9VqDM7DpGz`
	TXT	`docker-verification=0ebe0b8e-6bd1-4f94-b0b3-344bd07052ed`
	TXT	`docusign=1ddc2bf3-a249-4127-a351-f22dc75077d3`
	TXT	`ecostruxure-it-verification=881dfd3b-5776-4fc0-a5f6-190a0ac842f8`
	TXT	`f3n3z6cw35fkl9lnb6q72dczy2z7d2gy`
	TXT	`fastly-domain-delegation-0344411-343733-2021_0223`
	TXT	`globalsign-domain-verification=jpcnVg6kuHYyEz5op6ZzxI2E53gePoVqca7RgL0aNq`
	TXT	`google-site-verification=1eOMDGAH7nc_P5U-8MWPqSTU40og02u0CODDvbcmoMw`
	TXT	`google-site-verification=IqETr3m1Iq2apdhg2tJndtOH5xn_C0PrLSBL4UpB9WU`
	TXT	`google-site-verification=WMDRc5NQqj7RWff1N8L0_Ikc08kSr-iUa3C0Zczl9QA`
	TXT	`google-site-verification=Yse39yHdmcUPiSTGNVY-eI27sV3TBfQVLBPHGWHiins`
	TXT	`google-site-verification=_dm8lZJlohRuCXhYRFe8COWc0JNx7c6AVF1vWpP52nE`
	TXT	`google-site-verification=qKQzyXjxHLM4q1X-7PdrurR3p1QjjINz2QD_MBvAmyU`
	TXT	`google-site-verification=z4muhl35r1aT-msc5R269PO3RKaZHc7zzn6omxkiedI`
	TXT	`gwt5v1xngwj1f6zq7khv3bp4xnxbgmkg`
	TXT	`hpe-greenlake-domain-verification=34593547575036384f70456d3575724671644371615...`
	TXT	`intersight=f7b95d6ad5339839c1253d5e47c1c32ff8276909334ff7173890c54f4730e68a`
	TXT	`jamf-site-verification=ginKrX1WfPAXLoSWwmiYoA`
	TXT	`logmein-domain-confirmation 90DIFG9EEUT8U8R4895Y87H`
	TXT	`mandrill_verify.e-l764xQVEGJ2x07f-WGHg`
	TXT	`miro-verification=a08b425a7aa0b2b93256f4b504ee72afe8f9e0b9`
	TXT	`mongodb-site-verification=Edb8EnML5i9pqy6z4N7La044KKs2z3iC`
	TXT	`onetrust-domain-verification=3fce180bf9e54d5b97a7c9e1ce3cb10c`
	TXT	`openai-domain-verification=dv-L58PjwMLqJ4qWsOGfKRPglPO`
	TXT	`paloaltonetworks-site-verification=05d52539c7f02572db198a10ba1b238b6f4c6550c0...`
	TXT	`sending_domain1012722=80cff31442c5f4e1b9c51346939d5bf298d9eff5f69d465476631c9...`
	TXT	`smartsheet-site-validation=zF2Qh0qhBS3O7AjSZMdaAVW2E7GB1VLL`
	TXT	`v=spf1 include:%{ir}.%{v}.%{d}.spf.has.pphosted.com -all`
	TXT	`workplace-domain-verification=LsPqX88w148qQltQvOoT4ZTx6EO5Be`
	TXT	`wrike-verification=NDM5MTUzODoyMTFkNjJmZWM5MDk5MTVjOWY2YTQ2MWI4MmVhNjRkZjBmNj...`
	TXT	`x9zcxt1dfyz6jj60w7smwl42tjzfv5yn`
	SOA	`ns-1288.awsdns-33.org`awsdns-hostmaster@amazon.com serial=1

WOT: SAFE (91/100)
rank #211 globally
rank #136 in the tld

booking.com

booking.comis a major online travel agency website used for booking lodging, flights, car rentals, and other travel-related services. It is operated by Booking.com B.V., which is a subsidiary of Booking Holdings.

Key facts

Owner / operator: Booking Holdings
TLD:.com— gTLD
Primary purpose: Online travel agency and lodging reservations
Status: active

History

Year	Event
1996	Founded as Bookings.nl in the Netherlands.
2005	Acquired by Priceline Group (now Booking Holdings).
2018	Parent company Priceline Group changed its name to Booking Holdings.

Related domains

bookingholdings.com

🔒 HSTS Preload (+subdomains)
Semrush Rank:#196 Keywords:8,515,729 Traffic:13,320,385/mo
WOT: SAFE (91/100)
📈 Tranco rank: #260

Overview

Booking.com is the world's leading online travel agency, headquartered in Amsterdam, Netherlands. Founded in 1996, it operates as the flagship brand of Booking Holdings Inc. (NASDAQ: BKNG), serving travelers in over 220 countries and territories. The platform offers accommodations ranging from hotels and resorts to vacation rentals, apartments, and unique stays—with over 31 million listings worldwide.

Services

Accommodation Booking: Hotels, hostels, apartments, villas, and unique properties
Flight & Car Rentals: Integrated travel booking beyond lodging
Booking.com for Business: Corporate travel management solutions
Genius Loyalty Program: Tiered rewards system with discounts and perks
Travel Experiences: Activities and attractions at destinations

In 2024, Booking Holdings processed $166 billion in gross travel bookings and 1.1 billion room nights, employing over 24,000 people across 140+ nationalities.

Technical Infrastructure

Component	Provider
Nameservers	AWS Route 53 (ns-508, ns-716, ns-1288, ns-1959)
Web Hosting	Amazon CloudFront (18.154.144.x range)
Email Security	Proofpoint (mxa/mxb-0032a201.gslb.pphosted.com)
DNSSEC	Not enabled

The domain ranks #228 globally and #145 among .com domains by traffic.

PTR for

129.21.57.5.in-addr.arpa

DNS History

1 record (1 active, 0 former)

●A5.57.21.1292016-03-11 → 2026-06-28 · 2 obs

● 2016-03-11 15:54:00
● 2026-06-28 10:37:48

🔍 DNS Trace

📋 Delegation Chain

Zone	Nameservers	Glue
com	a.gtld-servers.net, l.gtld-servers.net, c.gtld-servers.net, d.gtld-servers.net...	-
booking.com	ns-716.awsdns-25.net, ns-508.awsdns-63.com, ns-1288.awsdns-33.org, ns-1959.awsdns-52.co.uk	2 records

✅ Authoritative Response

Server:205.251.197.8

NS records: ns-716.awsdns-25.net, ns-508.awsdns-63.com, ns-1288.awsdns-33.org, ns-1959.awsdns-52.co.uk

🔒 DNSSEC Status

⚠️ Insecure (no DNSSEC)

No DS record for booking.com (unsigned zone)

⏱️ Timing

Total: 262ms | Queries: -

📄 Records

Type	Count	Sample Data
A	1	`5.57.21.129`

📌 Glue Records Collected

Total: 2

Out-of-bailiwick: 2 (ns-508.awsdns-63.com, ns-508.awsdns-63.com)

Analysis

IP Addresses

proxy-out-a.booking.com points to a single IP number: 5.57.21.129.

proxy-out-a.booking.com - robtex.com