Dataweaz

bt.com

Summary

Registrar
Network Solutions, LLC
Status
clientTransferProhibited
Created on
June 18, 1992
Expires on
June 17, 2027
Name servers
DYDNS1.bt.com, EDDNS1.bt.com, DYDNS0.bt.com, EDDNS0.bt.com
Mail servers
btgroupcloud-mail-onmicrosoft-com.mail.protection.outlook.com
DMARC
Reject
SPF
Soft

Spoofing protection (DMARC)

Reject

E-mails spoofing this domain are rejected.

DMARC tells mail servers what to do with an e-mail that claims to come from bt.com but fails SPF and DKIM checks.

Policy
Reject
Subdomain policy
Reject
Messages covered
100%
DKIM alignment
Relaxed
SPF alignment
Relaxed

Record

v=DMARC1; p=reject; fo=1; rua=mailto:[email protected],mailto:[email protected]; ruf=mailto:[email protected],mailto:[email protected]

Authorized senders (SPF)

Soft

E-mails sent by any other server are accepted but flagged as suspicious.

SPF lists the servers allowed to send e-mails for bt.com.

RuleValueResult
includespf.protection.outlook.comAllowed
includewww.thrs.bt.comAllowed
includesmtp1.bt.comAllowed
ip462.7.242.136/29Allowed
ip462.239.224.234/31Allowed
ip462.239.224.236/31Allowed
ip462.239.224.98/31Allowed
ip4193.113.108.40/31Allowed
ip4212.140.59.179Allowed
ip4212.140.56.164Allowed
ip4212.49.128.65Allowed
ip4200.47.123.3Allowed
ip4147.149.196.177Allowed
ip4147.149.100.81Allowed
ip4147.149.196.181Allowed
ip4147.149.100.78Allowed
all—Suspicious

Top-level DNS lookups: 3 of 10 allowed

Record

v=spf1 include:spf.protection.outlook.com include:www.thrs.bt.com include:smtp1.bt.com ip4:62.7.242.136/29 ip4:62.239.224.234/31 ip4:62.239.224.236/31 ip4:62.239.224.98/31 ip4:193.113.108.40/31 ip4:212.140.59.179 ip4:212.140.56.164 ip4:212.49.128.65 ip4:200.47.123.3 ip4:147.149.196.177 ip4:147.149.100.81 ip4:147.149.196.181 ip4:147.149.100.78 ~all

E-mail signing (DKIM)

DKIM keys published by bt.com under the most common selectors. Other keys may exist under selectors specific to each sending service.

SelectorLikely serviceKeyStatus
selector1Microsoft 365RSA 1024 bits · shortActive
s1SendGridRSA 2048 bitsActive
s2SendGridRSA 2048 bitsActive

RSA keys shorter than 2048 bits, called short keys, are discouraged: they are easier to break.

MX, SPF, DKIM and DMARC: the e-mail records

Four DNS records make a domain's e-mail work. MX says where e-mails sent to bt.com arrive; SPF, DKIM and DMARC let mail servers check that an e-mail claiming to come from bt.com was really sent by this domain, which protects it against spoofing.

MX

An MX (Mail Exchanger) record designates a server that receives e-mails sent to the domain. When someone writes to an @bt.com address, their mail server queries the DNS for the domain's MX records, then delivers the message to the server they point to.

Example record

bt.com  MX  10 mx1.bt.com.
bt.com  MX  20 mx2.bt.com.

What the record contains

10, 20
Priority: the server with the lowest number is tried first. Servers with equal priority share the load.
mx1.bt.com.
Host name of the mail server. It must point to an A or AAAA record: an IP address or an alias (CNAME) is not allowed here.
0 .
An MX "0 .", called a null MX, declares that the domain accepts no e-mail: sending servers give up at once instead of retrying.

Declaring at least two servers with different priorities avoids losing e-mails during an outage: sending servers retry for several days and fall back on the backup server. Without any MX, they try to deliver directly to the IP address of the domain.

SPF

SPF (Sender Policy Framework) is a TXT record listing the servers allowed to send e-mails on behalf of the domain. The receiving server checks that the sender is on this list. The final "all" rule says what to do with other servers: reject them (-all), flag their e-mails as suspicious (~all) or make no decision (?all).

Example record

bt.com  TXT  "v=spf1 mx include:_spf.google.com ip4:192.0.2.10 -all"

What the record contains

v=spf1
Identifies the record as an SPF policy. It must come first.
ip4, ip6
Allows a specific IP address or an address range, for example ip4:192.0.2.0/24.
a, mx
Allows the addresses of the domain itself (A record) or those of its mail servers (MX).
include
Allows the servers of another domain, usually a sending service: include:_spf.google.com for Google Workspace.
-all, ~all
Final rule, applied to every other server. Its qualifier decides what happens to them: - rejects them, ~ flags their e-mails as suspicious, ? makes no decision, + accepts them (avoid it).

A domain must publish only one SPF record, and its evaluation cannot exceed 10 DNS lookups (include, a, mx, exists, redirect). Beyond that, mail servers treat it as invalid.

DKIM

DKIM (DomainKeys Identified Mail) signs every outgoing e-mail with a private key. The matching public key is published in a TXT record at selector._domainkey.bt.com, so the recipient can check that the message really comes from the domain and was not altered on the way. The selector is chosen by each sending service and cannot be guessed: Dataweaz checks the most common ones (Google Workspace, Microsoft 365, Mailchimp, SendGrid…), so a key published under another selector may exist without appearing here.

Example record

google._domainkey.bt.com  TXT  "v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA…"

What the record contains

v=DKIM1
Protocol version. Optional but recommended, in which case it must come first.
k
Key algorithm: rsa, the most common, or ed25519.
p
Public key, base64-encoded. An empty value means the key has been revoked.
t
Flags: y marks a key in testing, whose failures must not be penalized; s forbids its use for subdomains.

Each sending service publishes its key under its own selector (google, selector1, k1…), which allows several keys and seamless rotation. A 2048-bit RSA key is recommended today.

DMARC

DMARC (Domain-based Message Authentication, Reporting and Conformance) builds on SPF and DKIM. Published on _dmarc.bt.com, it tells mail servers what to do with an e-mail that fails these checks (let it through, send it to spam or reject it) and where to send reports.

Example record

_dmarc.bt.com  TXT  "v=DMARC1; p=quarantine; rua=mailto:[email protected]; adkim=r; aspf=r"

What the record contains

v=DMARC1
Identifies the record as a DMARC policy. It must come first.
p
Policy applied to e-mails that fail the checks: none (monitoring only), quarantine (spam folder) or reject.
sp
Subdomain policy. Without it, subdomains follow the domain's policy.
rua
Address that receives daily aggregate reports about e-mails sent on behalf of the domain, whether they pass the checks or not.
ruf
Address that receives detailed failure reports, message by message. Few providers still send them.
pct
Percentage of e-mails subject to the policy, for a gradual rollout. 100 by default.
adkim, aspf
DKIM and SPF alignment: r (relaxed, a subdomain of the same domain is enough) or s (strict, the domain must be identical).

To roll out DMARC without blocking legitimate e-mails, start with p=none and an rua address, analyze the reports to find every service sending on behalf of the domain, then move to quarantine and finally to reject.

DNS records of bt.com

IP addresses (A and AAAA)

An A record maps the domain name to an IPv4 address: the address of the server that browsers contact to display the website. The AAAA record does the same for an IPv6 address. A domain can have several of them to spread visits across several servers.

TypeIP address
A45.60.65.23
A45.60.72.23

Name servers (NS)

NS records designate the authoritative DNS servers of the domain: they answer every question about its other records (A, MX, TXT…). They are provided by the registrar, the hosting provider or a dedicated DNS service, and several servers are declared so that the domain keeps working if one of them fails.

ServerIP address
DYDNS1.bt.com193.113.32.157
EDDNS1.bt.com193.113.57.243
DYDNS0.bt.com193.113.32.156
EDDNS0.bt.com193.113.57.242

Mail servers (MX)

MX records point to the servers that receive e-mails sent to the domain, that is to @bt.com addresses. Each server has a priority: the one with the lowest number is tried first, the others take over if it fails. Without an MX record, the domain cannot receive e-mails.

PriorityServerIP address
10btgroupcloud-mail-onmicrosoft-com.mail.protection.outlook.com52.101.91.153

TXT records

TXT records hold free text. They are used to prove ownership of the domain to online services (Google, Microsoft, Facebook…) and to publish e-mail security rules: SPF on the domain itself, DMARC on _dmarc.bt.com.

NameContent
bt.com00D20000000NCwt=1TBWT00000000b7
bt.comVISA= A14484CFA0B3A9C074FDA5BCF4183B00
bt.com_tehgpyqfurfy5ch81uqgxy74ema16qu
bt.comautodesk-domain-verification=vmIPnr1GseHte8Ol4tdd
bt.comx6MWUs7ki3ZXYAZgVHRipb4Y7L33ZqthzG8Wbb4vSlE=
bt.com00D30000000nxrL=1TBcg00000002pp
bt.comglobalsign-domain-verification=93146127E3119923691CF830DC3A3E29
bt.comatlassian-sending-domain-verification=26d0f833-b724-4eb7-aeec-64a923fd0caf
bt.com_fu9wexpb3hl7k2jggs33dn43b3mbtum
bt.com_73xgrve35ztjj39vbx23u32up1gm42f
bt.comapple-domain-verification=2wmMLKFJFlWPklL2
bt.com_ymtss61d4gx4f58ecfnwl3d2ubjif58
bt.compaloaltonetworks-site-verification=4358a4575e5e2f27af9887fb7c598966be5752014419bcd03eaa89f5367f1e08
bt.com00D4K000001WhuT=1TBWT00000000w5;00D3G0000008auy=1TBUF00000001Dp;00D3M0000008awU=1TBQ1000000032k;00DVd000000Yncb=1TBVd000000012X;00DPt00000AHKKj=1TBPt000000085d;00DPu000007jSP7=1TBPu0000000AQp;00DS900000ADqmD=1TBS90000000BDB;00DVd000004dqyv=1TBVd00000007pV;00DUF000007HdiT=1TBUF0000000BDB
bt.com/vj9t5DVxv0tUwaf705CFBnmRbpkKzjSoqMMcQ4rLEdQVregGB7ilLMyW/YnvBCMkSL/B7XxEjYnlHL6o3Ln9A==
bt.com_9k4vppymta57qs1qkz8ioo2l3gx22p1
bt.com_rfekfxf1yes9bsgohx5au51nlhla5ob
bt.comMS187269
bt.comVISA= 54D62E662CD075058ACEB7C8D7E18208
bt.comglobalsign-domain-verification=272BF8C4C603422028B68384B658E886
bt.comvrelnrisb1a3v4qqq54fjbjbbs
bt.comatlassian-sending-domain-verification=ae1e2cb6-0959-4f25-b37a-4c66b4e5e468
bt.com00D30000000JJui=1TBWT00000000mP
bt.comMS442395
bt.comfacebook-domain-verification=6ismgdmuzqf1lp6gse48wa4oz2isw5
bt.com_666lwgd30fnhx8sp9n0vlg0o39yl9p3
bt.com_79jx6i3axwnposq6qclu511575r4b04
bt.comatlassian-domain-verification=XLWtzSfK6U83Hg5Um61jVLjNzqR9ygXELexMNfqJJshefny8hFi3KNAK/Hb4xAYl
bt.com9123-70F4-5236-027D-644B-81E0-D859-AECD
bt.com_m3f8ep2c1pbboco1rh90guadk9uqjla
bt.com_zggwxi2qwppqomie3645517zmcjghhc
bt.comMS173292
bt.comvmware-cloud-verification-be6dfc6d-61b7-4e1b-af28-e75a39c7fb50
bt.comglobalsign-domain-verification=CE9FD7B27BF880B6F922A3C2CC99BB0A
bt.comatlassian-domain-verification=3Gt5LVaXs8hMlqUYlA6GMNsniVorsulY5XFecUK/BLQg/DJOuntZxg7sjE4R38od
bt.com_o2c1d8i6qckztzgqsf0eiw0m6wngm78
bt.comv=spf1 include:spf.protection.outlook.com include:www.thrs.bt.com include:smtp1.bt.com ip4:62.7.242.136/29 ip4:62.239.224.234/31 ip4:62.239.224.236/31 ip4:62.239.224.98/31 ip4:193.113.108.40/31 ip4:212.140.59.179 ip4:212.140.56.164 ip4:212.49.128.65 ip4:200.47.123.3 ip4:147.149.196.177 ip4:147.149.100.81 ip4:147.149.196.181 ip4:147.149.100.78 ~all
bt.comqRopWoq/R1mmlrFP3CcfSGfW/3MIPo9zmLSfpe5jAM1aIHOzroByZqIVeColeWxGi3AFCqaTyCC0sE4r8N6o0A==
bt.comdtm-domain-verification=HykUdMm1ucjXduqd9uBIS35Us7ii2mDrjiqE5PqPhm4
bt.come_mKF3VwiervayPJ5VUm
bt.comapple-domain-verification=JCy70GnffQDcBVIR
bt.comMS514229
bt.comabusix-inc-domain-verification-2krgyn=z84EaQ48vKfAWBJptZi4Cjd2o
bt.comglobalsign-domain-verification=1931E8CBF9A676E73F6E753F40E7B872
bt.comgoogle-site-verification=G7I_80VRER7Wgn3V-aNWBFijdpE4JGSzMq_WlbrbN7Y
bt.comfastly-domain-delegation-wid9asosrymezhsoaxay-00645561-2026-03-20
bt.com_7z0ek0xby5dewx0vdggiubvqtnrbc1x
bt.com_c9dajtmpca7sm5f5nk0q5cordmlsy6q
bt.comfastly-domain-delegation-5Lazp7wYoooiwDL9dEWZ-422411-2021-07-22
bt.comapple-domain-verification=8qEsid9JR22QL8DO
bt.com_0j7861vbjb8la6jhqjo3y80pocnw2ce
bt.comonetrust-domain-verification=4e5dad68ca124ab68bc54c9a68781fa5
bt.comglobalsign-domain-verification=DAA742FBA19F6967D3D3A8DC2BE96867
bt.comDNRynrIWZj7FpJ7nTv6o0S9OiH9++PvCF6byh33McE4=
bt.comgoogle-site-verification=jqIuLoI2xscRdokU7DZrf026zMImlQIQwAHVT3bgMUk
bt.com_kgh0olda2pjev8kflb7p455dbzv2w03
bt.com_2m131ofp1dqn1d8ff97ufl265w6be3d
_dmarc.bt.comv=DMARC1; p=reject; fo=1; rua=mailto:[email protected],mailto:[email protected]; ruf=mailto:[email protected],mailto:[email protected]
selector1._domainkey.bt.comv=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDGclzMj/je/SuYUaxYE3YD1uwaNqgxTqqulk6zR8sU61kufK1pYnrnblDVqKkBS2+9KRuqxs4fbkmKgZAy30zi6+7tnUoJADWr+Rt6F9tFB9c5aLCmVkhj4UQFQk+5N8JDPRF/N1iRAFm9kLqUdxPcBxD5AoLuDHc3kOpevKPfXQIDAQAB;
s1._domainkey.bt.comk=rsa; t=s; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA0t/ylNaTRMECHg6P+oewlRyFOsUQlXKBC1QmoAajc/99lwvZrnlPFzfP39WsCvrjKfR5cQMLVrjtVK83EpWbwWi2qqUzvORnxDMjqI4Q7953JRZ2NEsJxKucXTERRVaz3ru+BY0dKYz3u61Hs1bDCaljXKxvoyJ8sCvqLYuAzK5GeIwaiQM8ZF0KDEEeT87523f90HL1jaNV/rfciSLssl8S7xKjurQFr8CzJ2bVD19SadXGQA8ucnNKBA2sMmKZvHNZk0eX9UawMZgaQyelBuvxw0HN308rsK2z8Y4+aXZBdipO6AN2VaP/LDVHOmllp1I1xjE/Qcfiz9IdX7r8bwIDAQAB
s2._domainkey.bt.comk=rsa; t=s; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAwZ6mvA9tR7oQ4bUdFFp1fw7va9OLd1eoo6bbV9Q2xoJADHpdyKdklPjOMu7ZopJjJKlkv6WGDn3Mdi0N6hgXaOr4Z8xpxCwzAp8W/qqwL9DjJFvbuG+U2CfC2b/o5n7YXpP+aWnsNdSoKfqBVDZTjoTQ7QQy5aZHMaT5FGYabnD0vod/VRZWf1BhT3CESTMYMCPSRorIhB+HxmMm0fqoqSbJ7U18gzsnf9Y/DbHzOzY9gjXiLGVfvaKYooJQOxwasOXFXjgOi6g1UrC6SpfNyZHIc/2qXGF1FKimIA+bWYfABUIyDGHHxnMiLBLmedkDwiH+h0++j2lxcV0N9wqW2QIDAQAB

Related IP addresses

IPv4 addresses used by bt.com: website, name servers, mail servers and senders authorized by SPF.

IP addressUsed for/24 block
45.60.65.23Website45.60.65.0/24
45.60.72.23Website45.60.72.0/24
193.113.32.157Name server DYDNS1.bt.com193.113.32.0/24
193.113.57.243Name server EDDNS1.bt.com193.113.57.0/24
193.113.32.156Name server DYDNS0.bt.com193.113.32.0/24
193.113.57.242Name server EDDNS0.bt.com193.113.57.0/24
52.101.91.153Mail server btgroupcloud-mail-onmicrosoft-com.mail.protection.outlook.com52.101.91.0/24
212.140.59.179Authorized by SPF212.140.59.0/24
212.140.56.164Authorized by SPF212.140.56.0/24
212.49.128.65Authorized by SPF212.49.128.0/24
200.47.123.3Authorized by SPF200.47.123.0/24
147.149.196.177Authorized by SPF147.149.196.0/24
147.149.100.81Authorized by SPF147.149.100.0/24
147.149.196.181Authorized by SPF147.149.196.0/24
147.149.100.78Authorized by SPF147.149.100.0/24

WHOIS of the domain bt.com

Domain Name: BT.COM
   Registry Domain ID: 180635_DOMAIN_COM-VRSN
   Registrar WHOIS Server: whois.networksolutions.com
   Registrar URL: http://networksolutions.com
   Updated Date: 2026-06-04T08:25:01Z
   Creation Date: 1992-06-18T04:00:00Z
   Registry Expiry Date: 2027-06-17T04:00:00Z
   Registrar: Network Solutions, LLC
   Registrar IANA ID: 2
   Registrar Abuse Contact Email: [email protected]
   Registrar Abuse Contact Phone: +1.8777228662
   Domain Status: clientTransferProhibited https://icann.org/epp#clientTransferProhibited
   Domain Status: serverDeleteProhibited https://icann.org/epp#serverDeleteProhibited
   Domain Status: serverTransferProhibited https://icann.org/epp#serverTransferProhibited
   Domain Status: serverUpdateProhibited https://icann.org/epp#serverUpdateProhibited
   Name Server: DYDNS0.BT.COM
   Name Server: DYDNS1.BT.COM
   Name Server: EDDNS0.BT.COM
   Name Server: EDDNS1.BT.COM
   DNSSEC: unsigned
   URL of the ICANN Whois Inaccuracy Complaint Form: https://www.icann.org/wicf/
>>> Last update of whois database: 2026-10-02T07:38:13Z <<<

For more information on Whois status codes, please visit https://icann.org/epp

NOTICE: The expiration date displayed in this record is the date the
registrar's sponsorship of the domain name registration in the registry is
currently set to expire. This date does not necessarily reflect the expiration
date of the domain name registrant's agreement with the sponsoring
registrar.  Users may consult the sponsoring registrar's Whois database to
view the registrar's reported date of expiration for this registration.

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