Summary
- Registrar
- MarkMonitor, Inc (TLDs)
- Status
- clientDeleteProhibited
- Created on
- May 17, 2018
- Expires on
- May 18, 2027
- Name servers
- dns2.p05.nsone.net, dns4.p05.nsone.net, dns3.p05.nsone.net, dns1.p05.nsone.net
- Mail servers
- —
- DKIM
- No key found among the common selectors
- Website
- See the website
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 github.blog arrive; SPF, DKIM and DMARC let mail servers check that an e-mail claiming to come from github.blog 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 @github.blog 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
github.blog MX 10 mx1.github.blog. github.blog MX 20 mx2.github.blog.
What the record contains
- 10, 20
- Priority: the server with the lowest number is tried first. Servers with equal priority share the load.
- mx1.github.blog.
- 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
github.blog 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.github.blog, 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.github.blog 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.github.blog, 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.github.blog 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 github.blog
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.
| Type | IP address |
|---|---|
| A | 192.0.66.2 |
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.
| Server | IP address |
|---|---|
| dns2.p05.nsone.net | 198.51.45.5 |
| dns4.p05.nsone.net | 198.51.45.69 |
| dns3.p05.nsone.net | 198.51.44.69 |
| dns1.p05.nsone.net | 198.51.44.5 |
Mail servers (MX)
MX records point to the servers that receive e-mails sent to the domain, that is to @github.blog 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.
No mail server: the domain does not receive e-mails.
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.github.blog.
| Name | Content |
|---|---|
| github.blog | google-site-verification=HPL8binrED5R9U3oyWqWsnVr1e2EI9hnKlLizQywIlQ |
Related IP addresses
IPv4 addresses used by github.blog: website, name servers, mail servers and senders authorized by SPF.
| IP address | Used for | /24 block |
|---|---|---|
| 192.0.66.2 | Website | 192.0.66.0/24 |
| 198.51.45.5 | Name server dns2.p05.nsone.net | 198.51.45.0/24 |
| 198.51.45.69 | Name server dns4.p05.nsone.net | 198.51.45.0/24 |
| 198.51.44.69 | Name server dns3.p05.nsone.net | 198.51.44.0/24 |
| 198.51.44.5 | Name server dns1.p05.nsone.net | 198.51.44.0/24 |
WHOIS of the domain github.blog
Domain Name: github.blog Registry Domain ID: 624983-BLOG Registrar WHOIS Server: whois.blog.fury.ca Registrar URL: markmonitor.com Updated Date: 2026-04-20T09:23:42Z Creation Date: 2018-05-17T01:42:57Z Registry Expiry Date: 2027-05-17T23:59:59Z Registrar: MarkMonitor, Inc (TLDs) Registrar IANA ID: 292 Registrar Abuse Contact Email: [email protected] Registrar Abuse Contact Phone: +1.2083895740 Registrar Abuse Contact Phone Ext: Domain Status: clientDeleteProhibited https://icann.org/epp#clientDeleteProhibited Domain Status: clientTransferProhibited https://icann.org/epp#clientTransferProhibited Domain Status: clientUpdateProhibited https://icann.org/epp#clientUpdateProhibited Registry Registrant ID: REDACTED FOR PRIVACY Registrant Name: REDACTED FOR PRIVACY Registrant Organization: Registrant Street: REDACTED FOR PRIVACY Registrant City: REDACTED FOR PRIVACY Registrant State/Province: Registrant Postal Code: REDACTED FOR PRIVACY Registrant Country: Registrant Phone: REDACTED FOR PRIVACY Registrant Phone Ext: REDACTED FOR PRIVACY Registrant Fax: REDACTED FOR PRIVACY Registrant Fax Ext: REDACTED FOR PRIVACY Registrant Email: Please ask the Registrar of Record identified in this output for information on how to contact the Registrant, Admin, or Other contacts of the queried domain name Registry Admin ID: REDACTED FOR PRIVACY Admin Name: REDACTED FOR PRIVACY Admin Organization: REDACTED FOR PRIVACY Admin Street: REDACTED FOR PRIVACY Admin City: REDACTED FOR PRIVACY Admin State/Province: REDACTED FOR PRIVACY Admin Postal Code: REDACTED FOR PRIVACY Admin Country: REDACTED FOR PRIVACY Admin Phone: REDACTED FOR PRIVACY Admin Phone Ext: REDACTED FOR PRIVACY Admin Fax: REDACTED FOR PRIVACY Admin Fax Ext: REDACTED FOR PRIVACY Admin Email: Please ask the Registrar of Record identified in this output for information on how to contact the Registrant, Admin, or Other contacts of the queried domain name Registry Tech ID: REDACTED FOR PRIVACY Tech Name: REDACTED FOR PRIVACY Tech Organization: REDACTED FOR PRIVACY Tech Street: REDACTED FOR PRIVACY Tech City: REDACTED FOR PRIVACY Tech State/Province: REDACTED FOR PRIVACY Tech Postal Code: REDACTED FOR PRIVACY Tech Country: REDACTED FOR PRIVACY Tech Phone: REDACTED FOR PRIVACY Tech Phone Ext: REDACTED FOR PRIVACY Tech Fax: REDACTED FOR PRIVACY Tech Fax Ext: REDACTED FOR PRIVACY Tech Email: Please ask the Registrar of Record identified in this output for information on how to contact the Registrant, Admin, or Other contacts of the queried domain name Registry Billing ID: REDACTED FOR PRIVACY Billing Name: REDACTED FOR PRIVACY Billing Organization: REDACTED FOR PRIVACY Billing Street: REDACTED FOR PRIVACY Billing City: REDACTED FOR PRIVACY Billing State/Province: REDACTED FOR PRIVACY Billing Postal Code: REDACTED FOR PRIVACY Billing Country: REDACTED FOR PRIVACY Billing Phone: REDACTED FOR PRIVACY Billing Phone Ext: REDACTED FOR PRIVACY Billing Fax: REDACTED FOR PRIVACY Billing Fax Ext: REDACTED FOR PRIVACY Billing Email: Please ask the Registrar of Record identified in this output for information on how to contact the Registrant, Admin, or Other contacts of the queried domain name Name Server: dns1.p05.nsone.net Name Server: dns2.p05.nsone.net Name Server: dns3.p05.nsone.net Name Server: dns4.p05.nsone.net DNSSEC: unsigned URL of the ICANN Whois Inaccuracy Complaint Form: https://www.icann.org/wicf/ >>> Last update of WHOIS database: 2026-10-01T03:34:07Z <<< For more information on Whois status codes, please visit https://icann.org/epp % % Use of CIRA's WHOIS service is governed by the Terms of Use in its Legal % Notice, available at https://www.cira.ca/en/resources/documents/about/website-terms-use % % (c) 2026 Canadian Internet Registration Authority, (http://www.cira.ca/) Domain Name: github.blog Registry Domain ID: 624983-BLOG Registrar WHOIS Server: whois.blog.fury.ca Registrar URL: markmonitor.com Updated Date: 2026-04-20T09:23:42Z Creation Date: 2018-05-17T01:42:57Z Registry Expiry Date: 2027-05-17T23:59:59Z Registrar: MarkMonitor, Inc (TLDs) Registrar IANA ID: 292 Registrar Abuse Contact Email: [email protected] Registrar Abuse Contact Phone: +1.2083895740 Registrar Abuse Contact Phone Ext: Domain Status: clientDeleteProhibited https://icann.org/epp#clientDeleteProhibited Domain Status: clientTransferProhibited https://icann.org/epp#clientTransferProhibited Domain Status: clientUpdateProhibited https://icann.org/epp#clientUpdateProhibited Registry Registrant ID: REDACTED FOR PRIVACY Registrant Name: REDACTED FOR PRIVACY Registrant Organization: Registrant Street: REDACTED FOR PRIVACY Registrant City: REDACTED FOR PRIVACY Registrant State/Province: Registrant Postal Code: REDACTED FOR PRIVACY Registrant Country: Registrant Phone: REDACTED FOR PRIVACY Registrant Phone Ext: REDACTED FOR PRIVACY Registrant Fax: REDACTED FOR PRIVACY Registrant Fax Ext: REDACTED FOR PRIVACY Registrant Email: Please ask the Registrar of Record identified in this output for information on how to contact the Registrant, Admin, or Other contacts of the queried domain name Registry Admin ID: REDACTED FOR PRIVACY Admin Name: REDACTED FOR PRIVACY Admin Organization: REDACTED FOR PRIVACY Admin Street: REDACTED FOR PRIVACY Admin City: REDACTED FOR PRIVACY Admin State/Province: REDACTED FOR PRIVACY Admin Postal Code: REDACTED FOR PRIVACY Admin Country: REDACTED FOR PRIVACY Admin Phone: REDACTED FOR PRIVACY Admin Phone Ext: REDACTED FOR PRIVACY Admin Fax: REDACTED FOR PRIVACY Admin Fax Ext: REDACTED FOR PRIVACY Admin Email: Please ask the Registrar of Record identified in this output for information on how to contact the Registrant, Admin, or Other contacts of the queried domain name Registry Tech ID: REDACTED FOR PRIVACY Tech Name: REDACTED FOR PRIVACY Tech Organization: REDACTED FOR PRIVACY Tech Street: REDACTED FOR PRIVACY Tech City: REDACTED FOR PRIVACY Tech State/Province: REDACTED FOR PRIVACY Tech Postal Code: REDACTED FOR PRIVACY Tech Country: REDACTED FOR PRIVACY Tech Phone: REDACTED FOR PRIVACY Tech Phone Ext: REDACTED FOR PRIVACY Tech Fax: REDACTED FOR PRIVACY Tech Fax Ext: REDACTED FOR PRIVACY Tech Email: Please ask the Registrar of Record identified in this output for information on how to contact the Registrant, Admin, or Other contacts of the queried domain name Registry Billing ID: REDACTED FOR PRIVACY Billing Name: REDACTED FOR PRIVACY Billing Organization: REDACTED FOR PRIVACY Billing Street: REDACTED FOR PRIVACY Billing City: REDACTED FOR PRIVACY Billing State/Province: REDACTED FOR PRIVACY Billing Postal Code: REDACTED FOR PRIVACY Billing Country: REDACTED FOR PRIVACY Billing Phone: REDACTED FOR PRIVACY Billing Phone Ext: REDACTED FOR PRIVACY Billing Fax: REDACTED FOR PRIVACY Billing Fax Ext: REDACTED FOR PRIVACY Billing Email: Please ask the Registrar of Record identified in this output for information on how to contact the Registrant, Admin, or Other contacts of the queried domain name Name Server: dns1.p05.nsone.net Name Server: dns2.p05.nsone.net Name Server: dns3.p05.nsone.net Name Server: dns4.p05.nsone.net DNSSEC: unsigned URL of the ICANN Whois Inaccuracy Complaint Form: https://www.icann.org/wicf/ >>> Last update of WHOIS database: 2026-10-01T03:34:07Z <<< For more information on Whois status codes, please visit https://icann.org/epp % % Use of CIRA's WHOIS service is governed by the Terms of Use in its Legal % Notice, available at https://www.cira.ca/en/resources/documents/about/website-terms-use % % (c) 2026 Canadian Internet Registration Authority, (http://www.cira.ca/) % Query time: 802 msec % WHEN: Thu Oct 01 03:34:06 UTC 2026