DMARC & SPF Lookup
Enter a domain to retrieve its DMARC and SPF records, validate every tag and mechanism, and see what’s worth fixing.
DMARC
Tells receivers what to do when authentication fails
Enforcement
Partial enforcement
Domain policy
quarantine
Subdomain policy
reject
Aggregate reporting
1 aggregate address
Published record
v=DMARC1; p=quarantine; sp=reject; pct=100; rua=mailto:dmarc@github.com; ruf=mailto:dmarc@github.com; fo=1
Warnings
Valid, but weaker than it could be.
- Policy is not at full enforcementp=quarantine sends failing mail to spam rather than blocking it. p=reject is the end goal once reports confirm your legitimate senders are aligned.
Tag breakdown
| Tag | Value | Meaning |
|---|---|---|
| v | DMARC1 | Version Protocol version. Must be DMARC1 and must be the first tag, or the whole record is ignored. |
| p | quarantine | Policy What receivers should do with mail that fails DMARC: none (monitor only), quarantine (treat as suspicious) or reject (block). |
| sp | reject | Subdomain policy Policy applied to subdomains. Defaults to the value of p when omitted. |
| pct | 100 | Percentage Portion of failing mail the policy applies to (0–100). Anything below 100 means most failing mail is not acted on. |
| rua | mailto:dmarc@github.com | Aggregate report address Where daily aggregate (RUA) XML reports are sent. Without it you get no visibility into your mail flows. |
| ruf | mailto:dmarc@github.com | Forensic report address Where per-message failure (RUF) reports are sent. Many providers never send these, and reports may contain message content. |
| fo | 1 | Failure options When to generate failure reports: 0 (all mechanisms fail), 1 (any mechanism fails), d (DKIM fails), s (SPF fails). |
| adkim default | r | DKIM alignment How strictly the DKIM domain must match the From domain: r (relaxed, subdomains allowed) or s (strict, exact match). |
| aspf default | r | SPF alignment How strictly the SPF domain must match the From domain: r (relaxed, subdomains allowed) or s (strict, exact match). |
| ri default | 86400 | Report interval Requested seconds between aggregate reports. Defaults to 86400 (daily); most receivers send daily regardless. |
Rows marked default are not in the record; these are the values receivers assume.
SPF
Lists the servers allowed to send mail for the domain
DNS lookups
10 / 10
Unlisted senders
~all (softfail)
Includes
9
Nested records
9
Published record
v=spf1 ip4:192.30.252.0/22 include:spf.protection.outlook.com include:_netblocks.google.com include:_netblocks2.google.com include:mail.zendesk.com include:_spf.salesforce.com include:servers.mcsv.net include:mktomail.com include:sendgrid.net ip4:62.253.227.114 ip4:166.78.69.169 ip4:166.78.69.170 ip4:166.78.71.131 ~all
Worth knowing
- Unlisted senders are soft-failed~all marks unlisted senders as suspicious rather than forbidden. That is the right setting while you are still discovering senders; tighten to -all once your DMARC reports are clean.
- Record exceeds 255 charactersIt must be published as multiple quoted strings within a single TXT record. Check your DNS provider handled the split.
Mechanism breakdown
| Term | Cost | Meaning |
|---|---|---|
| ip4:192.30.252.0/22 | free | Authorises an IPv4 address or range. Costs no lookup. |
| include:spf.protection.outlook.com | 1 lookup | Authorises another domain’s SPF record as well. Costs one DNS lookup, plus every lookup inside it. |
| include:_netblocks.google.com | 1 lookup | Authorises another domain’s SPF record as well. Costs one DNS lookup, plus every lookup inside it. |
| include:_netblocks2.google.com | 1 lookup | Authorises another domain’s SPF record as well. Costs one DNS lookup, plus every lookup inside it. |
| include:mail.zendesk.com | 1 lookup | Authorises another domain’s SPF record as well. Costs one DNS lookup, plus every lookup inside it. |
| include:_spf.salesforce.com | 1 lookup | Authorises another domain’s SPF record as well. Costs one DNS lookup, plus every lookup inside it. |
| include:servers.mcsv.net | 1 lookup | Authorises another domain’s SPF record as well. Costs one DNS lookup, plus every lookup inside it. |
| include:mktomail.com | 1 lookup | Authorises another domain’s SPF record as well. Costs one DNS lookup, plus every lookup inside it. |
| include:sendgrid.net | 1 lookup | Authorises another domain’s SPF record as well. Costs one DNS lookup, plus every lookup inside it. |
| ip4:62.253.227.114 | free | Authorises an IPv4 address or range. Costs no lookup. |
| ip4:166.78.69.169 | free | Authorises an IPv4 address or range. Costs no lookup. |
| ip4:166.78.69.170 | free | Authorises an IPv4 address or range. Costs no lookup. |
| ip4:166.78.71.131 | free | Authorises an IPv4 address or range. Costs no lookup. |
| ~all | free | Matches everything else. Its qualifier decides what happens to mail from any server not listed above. |
Include resolution
Every record reached while evaluating this domain. Each nested record spends lookups from the same budget of 10.
-
spf.protection.outlook.com no further lookups
v=spf1 ip4:40.92.0.0/15 ip4:40.107.0.0/16 ip4:52.100.0.0/15 ip4:52.102.0.0/16 ip4:52.103.0.0/17 ip4:104.47.0.0/17 ip6:2a01:111:f400::/48 ip6:2a01:111:f403::/49 ip6:2a01:111:f403:8000::/51 ip6:2a01:111:f403:c000::/51 ip6:2a01:111:f403:f000::/52 -all -
_netblocks.google.com no further lookups
v=spf1 ip4:74.125.0.0/16 ip4:209.85.128.0/17 ~all -
_netblocks2.google.com no further lookups
v=spf1 ip6:2001:4860:4000::/36 ip6:2404:6800:4000::/36 ip6:2607:f8b0:4000::/36 ip6:2800:3f0:4000::/36 ip6:2a00:1450:4000::/36 ip6:2c0f:fb50:4000::/36 ~all -
mail.zendesk.com no further lookups
v=spf1 ip4:103.151.192.0/23 ip4:185.12.80.0/22 ip4:188.172.128.0/20 ip4:192.161.144.0/20 ip4:216.198.0.0/18 ~all -
_spf.salesforce.com 1 further lookup
v=spf1 exists:%{i}._spf.mta.salesforce.com -all -
servers.mcsv.net no further lookups
v=spf1 ip4:205.201.128.0/20 ip4:198.2.128.0/18 ip4:148.105.0.0/16 -all -
mktomail.com no further lookups
v=spf1 ip4:199.15.212.0/22 ip4:72.3.185.0/24 ip4:72.32.154.0/24 ip4:72.32.217.0/24 ip4:72.32.243.0/24 ip4:94.236.119.0/26 ip4:37.188.97.188/32 ip4:185.28.196.0/22 ip4:192.28.128.0/18 ip4:103.237.104.0/22 ip4:130.248.172.0/24 ip4:130.248.173.0/24 ~all -
sendgrid.net 1 further lookup
v=spf1 ip4:167.89.0.0/17 ip4:208.117.48.0/20 ip4:50.31.32.0/19 ip4:198.37.144.0/20 ip4:198.21.0.0/21 ip4:192.254.112.0/20 ip4:168.245.0.0/17 ip4:149.72.0.0/16 ip4:159.183.0.0/16 ip4:134.128.64.0/18 ip4:159.26.176.0/20 include:ab.sendgrid.net ~all -
ab.sendgrid.net no further lookups
v=spf1 ip4:223.165.113.0/24 ip4:223.165.115.0/24 ip4:223.165.118.0/23 ip4:223.165.120.0/23 ~all