DNS Lookup Tool

Query comprehensive DNS records for any domain. Get A, AAAA, MX, TXT, NS, CAA, SRV, DNSKEY and more.

Try:

RequestGuard

DNS Records for substack.com

Records: 20

Response Time: 18ms

DNSSEC: Disabled

DNS Provider:

Cloudflare

Security: ✓ SPF soft ✓ DMARC reject

Address Records

IP addresses the domain points to

4 records

Type	Name	Value	TTL
A	substack.com	172.64.150.56 🇺🇸 US AS13335 CLOUDFLARENET - Cloudflare, Inc., US	5m
A	substack.com	104.18.37.200 🇺🇸 US AS13335 CLOUDFLARENET - Cloudflare, Inc., US	5m
AAAA	substack.com	2606:4700:440b::6812:25c8	5m
AAAA	substack.com	2606:4700:4400::ac40:9638	5m

Mail Records

Mail servers for the domain

2 records

Type	Name	Value	TTL
MX	substack.com	10 mxa.mailgun.org.	5m
MX	substack.com	10 mxb.mailgun.org.	5m

Name Records

Nameservers and aliases

3 records

Type	Name	Value	TTL
NS	substack.com	ali.ns.cloudflare.com.	1d
NS	substack.com	lee.ns.cloudflare.com.	1d
SOA	substack.com	ali.ns.cloudflare.com. dns.cloudflare.com. 2399990522 10000 2400 604800 1800	30m

Text & Verification

SPF, DKIM, DMARC, and verification

10 records

Type	Name	Value	TTL
TXT	_dmarc.substack.com	"v=DMARC1; p=reject; pct=100; rua=mailto:re+kvnosxqvppz@dmarc.postmarkapp.com; sp=reject; aspf=r;"	5m
TXT	substack.com	"facebook-domain-verification=8vbxp2ntmkudc6is3h5r840c9fwo7f"	5m
TXT	substack.com	"google-site-verification=4V_X38Yf0J4VJcWFwtG38bOS1nkOWeIWJhticlMgNQE"	5m
TXT	substack.com	"google-site-verification=DAkdykID6WqQM6tT7IfSu9_uB7-qIdB039MA_C3T3eA"	5m
TXT	substack.com	"google-site-verification=FfNIQIxsRHpj3Y7E_d3N6GFqGgWDZ-sfYojqCilwtqE"	5m
TXT	substack.com	"google-site-verification=SXEl7_p4SBszcanSWwVc_3-RFky80c0-94janbeeWI4"	5m
TXT	substack.com	"google-site-verification=vQEKLOUDfKNOQAv9W3EUMiRD6e5ibAEPhc2yCzP7big"	5m
TXT	substack.com	"tiktok-developers-site-verification=7PgqCAJ52ILLOqf2KELd8uaRfJpuzaLQ"	5m
TXT	substack.com	"tiktok-developers-site-verification=A9XRSo8lWy5CPFJ0bqI04KCpUZGAAq7p"	5m
TXT	substack.com	"v=spf1 include:_spf.google.com include:mailgun.org include:mail.zendesk.com ~all"	5m

Service Discovery

Service endpoints and bindings

1 record

Type	Name	Value	TTL
HTTPS	substack.com	\# 61 00 01 00 00 01 00 06 02 68 33 02 68 32 00 04 00 08 68 12 25 c8 ac 40 96 38 00 06 00 20 26 06 47 00 44 00 00 00 00 00 00 00 ac 40 96 38 26 06 47 00 44 0b 00 00 00 00 00 00 68 12 25 c8	5m

Queried at 5/12/2026, 8:52:41 AM

About DNS Records

The Domain Name System (DNS) is the internet's phonebook, translating human-readable domain names into IP addresses. DNS records contain essential configuration for how a domain behaves across email, web, security, and services.

Common Records

A/AAAA - Map domain to IPv4/IPv6 addresses
MX - Mail servers for receiving email
TXT - SPF, DKIM, DMARC for email security
NS - Authoritative nameservers
CNAME - Aliases pointing to other domains

Security Records

CAA - Restrict which CAs can issue certificates
DNSKEY/DS - DNSSEC cryptographic keys
TLSA - DANE TLS certificate authentication
SSHFP - SSH host key fingerprints
SRV - Service discovery and endpoints

REST API

Integrate DNS lookups into your applications with our REST API. Query all record types programmatically.

GET DNS Lookup

$ curl https://api.requestguard.com/v1/dns/lookup?domain=substack.com

Response for substack.com Live Data

{
  "success": true,
  "data": {
    "domain": "substack.com",
    "queryTimeMs": 18,
    "dnssec": false,
    "dnsProvider": "Cloudflare",
    "records": [
      {
        "type": "A",
        "name": "substack.com",
        "value": "172.64.150.56",
        "ttl": 300,
        "geo": {
          "ip": "172.64.150.56",
          "asn": 13335,
          "country": "US",
          "asnName": "CLOUDFLARENET - Cloudflare, Inc., US"
        }
      },
      {
        "type": "A",
        "name": "substack.com",
        "value": "104.18.37.200",
        "ttl": 300,
        "geo": {
          "ip": "104.18.37.200",
          "asn": 13335,
          "country": "US",
          "asnName": "CLOUDFLARENET - Cloudflare, Inc., US"
        }
      },
      {
        "type": "AAAA",
        "name": "substack.com",
        "value": "2606:4700:440b::6812:25c8",
        "ttl": 300,
        "geo": {
          "ip": "2606:4700:440b::6812:25c8"
        }
      },
      {
        "type": "AAAA",
        "name": "substack.com",
        "value": "2606:4700:4400::ac40:9638",
        "ttl": 300,
        "geo": {
          "ip": "2606:4700:4400::ac40:9638"
        }
      },
      {
        "type": "MX",
        "name": "substack.com",
        "value": "10 mxa.mailgun.org.",
        "ttl": 300
      },
      {
        "type": "MX",
        "name": "substack.com",
        "value": "10 mxb.mailgun.org.",
        "ttl": 300
      },
      {
        "type": "NS",
        "name": "substack.com",
        "value": "ali.ns.cloudflare.com.",
        "ttl": 86400
      },
      {
        "type": "NS",
        "name": "substack.com",
        "value": "lee.ns.cloudflare.com.",
        "ttl": 86400
      },
      {
        "type": "SOA",
        "name": "substack.com",
        "value": "ali.ns.cloudflare.com. dns.cloudflare.com. 2399990522 10000 2400 604800 1800",
        "ttl": 1800
      },
      {
        "type": "TXT",
        "name": "_dmarc.substack.com",
        "value": "\"v=DMARC1; p=reject; pct=100; rua=mailto:re+kvnosxqvppz@dmarc.postmarkapp.com; sp=reject; aspf=r;\"",
        "ttl": 300
      },
      {
        "type": "TXT",
        "name": "substack.com",
        "value": "\"facebook-domain-verification=8vbxp2ntmkudc6is3h5r840c9fwo7f\"",
        "ttl": 300
      },
      {
        "type": "TXT",
        "name": "substack.com",
        "value": "\"google-site-verification=4V_X38Yf0J4VJcWFwtG38bOS1nkOWeIWJhticlMgNQE\"",
        "ttl": 300
      },
      {
        "type": "TXT",
        "name": "substack.com",
        "value": "\"google-site-verification=DAkdykID6WqQM6tT7IfSu9_uB7-qIdB039MA_C3T3eA\"",
        "ttl": 300
      },
      {
        "type": "TXT",
        "name": "substack.com",
        "value": "\"google-site-verification=FfNIQIxsRHpj3Y7E_d3N6GFqGgWDZ-sfYojqCilwtqE\"",
        "ttl": 300
      },
      {
        "type": "TXT",
        "name": "substack.com",
        "value": "\"google-site-verification=SXEl7_p4SBszcanSWwVc_3-RFky80c0-94janbeeWI4\"",
        "ttl": 300
      },
      {
        "type": "TXT",
        "name": "substack.com",
        "value": "\"google-site-verification=vQEKLOUDfKNOQAv9W3EUMiRD6e5ibAEPhc2yCzP7big\"",
        "ttl": 300
      },
      {
        "type": "TXT",
        "name": "substack.com",
        "value": "\"tiktok-developers-site-verification=7PgqCAJ52ILLOqf2KELd8uaRfJpuzaLQ\"",
        "ttl": 300
      },
      {
        "type": "TXT",
        "name": "substack.com",
        "value": "\"tiktok-developers-site-verification=A9XRSo8lWy5CPFJ0bqI04KCpUZGAAq7p\"",
        "ttl": 300
      },
      {
        "type": "TXT",
        "name": "substack.com",
        "value": "\"v=spf1 include:_spf.google.com include:mailgun.org include:mail.zendesk.com ~all\"",
        "ttl": 300
      },
      {
        "type": "HTTPS",
        "name": "substack.com",
        "value": "\\# 61 00 01 00 00 01 00 06 02 68 33 02 68 32 00 04 00 08 68 12 25 c8 ac 40 96 38 00 06 00 20 26 06 47 00 44 00 00 00 00 00 00 00 ac 40 96 38 26 06 47 00 44 0b 00 00 00 00 00 00 68 12 25 c8",
        "ttl": 300
      }
    ],
    "queriedAt": "2026-05-12T08:52:41.236Z"
  }
}

Rate limit: 100 req/min

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