Summary
- Registrar
- CSC Corporate Domains, Inc.
- Status
- clientTransferProhibited
- Created on
- September 25, 1997
- Expires on
- September 24, 2027
- Name servers
- dns101.comcast.net, dns105.comcast.net, dns104.comcast.net, dns103.comcast.net, dns102.comcast.net
- Mail servers
- mx1.mxge.comcast.net, mx2.mxge.comcast.net, mx1h1.comcast.net, mx2h1.comcast.net, mx1c1.comcast.net, mx2a1.comcast.net, mx2c1.comcast.net, mx1a1.comcast.net
- DMARC
- Reject
- SPF
- Soft
- DKIM
- No key found among the common selectors
- Website
- See the website
Spoofing protection (DMARC)
E-mails spoofing this domain are rejected.
DMARC tells mail servers what to do with an e-mail that claims to come from comcast.net but fails SPF and DKIM checks.
- Policy
- Reject
- Subdomain policy
- Reject
- Messages covered
- 100%
- DKIM alignment
- Relaxed
- SPF alignment
- Relaxed
- Aggregate reports
- [email protected]
- Failure reports
- —
Record
v=DMARC1;p=reject;sp=reject;rua=mailto:[email protected]
Authorized senders (SPF)
E-mails sent by any other server are accepted but flagged as suspicious.
SPF lists the servers allowed to send e-mails for comcast.net.
| Rule | Value | Result |
|---|---|---|
| ip4 | 96.103.146.48/28 | Allowed |
| ip4 | 96.102.19.32/28 | Allowed |
| ip4 | 96.102.200.0/28 | Allowed |
| include | _spfv6.comcast.net | Allowed |
| include | _spf.mdp.comcast.net | Allowed |
| include | _ipspf.yahoo.com | Allowed |
| all | — | Suspicious |
Top-level DNS lookups: 3 of 10 allowed
Record
v=spf1 ip4:96.103.146.48/28 ip4:96.102.19.32/28 ip4:96.102.200.0/28 include:_spfv6.comcast.net include:_spf.mdp.comcast.net include:_ipspf.yahoo.com ~all
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 comcast.net arrive; SPF, DKIM and DMARC let mail servers check that an e-mail claiming to come from comcast.net 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 @comcast.net 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
comcast.net MX 10 mx1.comcast.net. comcast.net MX 20 mx2.comcast.net.
What the record contains
- 10, 20
- Priority: the server with the lowest number is tried first. Servers with equal priority share the load.
- mx1.comcast.net.
- 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
comcast.net 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.comcast.net, 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.comcast.net 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.comcast.net, 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.comcast.net 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 comcast.net
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 | 96.99.240.167 |
| AAAA | 2001:558:feed:dc:96:99:240:167 |
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 |
|---|---|
| dns101.comcast.net | 69.252.250.103 |
| dns105.comcast.net | 68.87.72.244 |
| dns104.comcast.net | 68.87.68.244 |
| dns103.comcast.net | 68.87.76.228 |
| dns102.comcast.net | 68.87.85.132 |
Mail servers (MX)
MX records point to the servers that receive e-mails sent to the domain, that is to @comcast.net 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.
| Priority | Server | IP address |
|---|---|---|
| 5 | mx1.mxge.comcast.net | 96.102.157.180 |
| 5 | mx2.mxge.comcast.net | 96.102.157.181 |
| 50 | mx1h1.comcast.net | 96.102.157.181 |
| 50 | mx2h1.comcast.net | 96.102.157.180 |
| 50 | mx1c1.comcast.net | 96.102.18.147 |
| 50 | mx2a1.comcast.net | 96.103.145.162 |
| 50 | mx2c1.comcast.net | 96.102.18.146 |
| 50 | mx1a1.comcast.net | 96.103.145.163 |
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.comcast.net.
| Name | Content |
|---|---|
| comcast.net | yahoo-verification-key=t0ftaXXV8MB1pon3jzauB3Fz5ezusB2l9jy3GVNPQRw= |
| comcast.net | v=spf1 ip4:96.103.146.48/28 ip4:96.102.19.32/28 ip4:96.102.200.0/28 include:_spfv6.comcast.net include:_spf.mdp.comcast.net include:_ipspf.yahoo.com ~all |
| comcast.net | google-site-verification=g7KA0NF2z-1XIBz7vWW88zvVYlJeiG56UPOYHF2tqY0 |
| comcast.net | google-site-verification=gxiEHT6grgMJE52lhl4OYIt5Q3XpA5qt-8Okrxq-mcE |
| _dmarc.comcast.net | v=DMARC1;p=reject;sp=reject;rua=mailto:[email protected] |
Related IP addresses
IPv4 addresses used by comcast.net: website, name servers, mail servers and senders authorized by SPF.
| IP address | Used for | /24 block |
|---|---|---|
| 96.99.240.167 | Website | 96.99.240.0/24 |
| 69.252.250.103 | Name server dns101.comcast.net | 69.252.250.0/24 |
| 68.87.72.244 | Name server dns105.comcast.net | 68.87.72.0/24 |
| 68.87.68.244 | Name server dns104.comcast.net | 68.87.68.0/24 |
| 68.87.76.228 | Name server dns103.comcast.net | 68.87.76.0/24 |
| 68.87.85.132 | Name server dns102.comcast.net | 68.87.85.0/24 |
| 96.102.157.180 | Mail server mx1.mxge.comcast.net, Mail server mx2h1.comcast.net | 96.102.157.0/24 |
| 96.102.157.181 | Mail server mx2.mxge.comcast.net, Mail server mx1h1.comcast.net | 96.102.157.0/24 |
| 96.102.18.147 | Mail server mx1c1.comcast.net | 96.102.18.0/24 |
| 96.103.145.162 | Mail server mx2a1.comcast.net | 96.103.145.0/24 |
| 96.102.18.146 | Mail server mx2c1.comcast.net | 96.102.18.0/24 |
| 96.103.145.163 | Mail server mx1a1.comcast.net | 96.103.145.0/24 |
WHOIS of the domain comcast.net
Domain Name: COMCAST.NET Registry Domain ID: 500652_DOMAIN_NET-VRSN Registrar WHOIS Server: whois.corporatedomains.com Registrar URL: http://cscdbs.com Updated Date: 2026-09-20T05:14:43Z Creation Date: 1997-09-25T04:00:00Z Registry Expiry Date: 2027-09-24T04:00:00Z Registrar: CSC Corporate Domains, Inc. Registrar IANA ID: 299 Registrar Abuse Contact Email: [email protected] Registrar Abuse Contact Phone: 8887802723 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: DNS101.COMCAST.NET Name Server: DNS102.COMCAST.NET Name Server: DNS103.COMCAST.NET Name Server: DNS104.COMCAST.NET Name Server: DNS105.COMCAST.NET DNSSEC: signedDelegation DNSSEC DS Data: 13484 13 2 9160C5B68EA46751A1DF0D203CAE66B938B68E3C50E0BDA5DC4EAEFE54583952 URL of the ICANN Whois Inaccuracy Complaint Form: https://www.icann.org/wicf/ >>> Last update of whois database: 2026-09-30T14:45:13Z <<< 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. TERMS OF USE: You are not authorized to access or query our Whois database through the use of electronic processes that are high-volume and automated except as reasonably necessary to register domain names or modify existing registrations; the Data in VeriSign Global Registry Services' ("VeriSign") Whois database is provided by VeriSign for information purposes only, and to assist persons in obtaining information about or related to a domain name registration record. VeriSign does not guarantee its accuracy. By submitting a Whois query, you agree to abide by the following terms of use: You agree that you may use this Data only for lawful purposes and that under no circumstances will you use this Data to: (1) allow, enable, or otherwise support the transmission of mass unsolicited, commercial advertising or solicitations via e-mail, telephone, or facsimile; or (2) enable high volume, automated, electronic processes that apply to VeriSign (or its computer systems). The compilation, repackaging, dissemination or other use of this Data is expressly prohibited without the prior written consent of VeriSign. You agree not to use electronic processes that are automated and high-volume to access or query the Whois database except as reasonably necessary to register domain names or modify existing registrations. VeriSign reserves the right to restrict your access to the Whois database in its sole discretion to ensure operational stability. VeriSign may restrict or terminate your access to the Whois database for failure to abide by these terms of use. VeriSign reserves the right to modify these terms at any time. The Registry database contains ONLY .COM, .NET, .EDU domains and Registrars.