github.com
Live email deliverability and anti-spoofing audit. Every value below was read from public DNS at the moment this page was generated.
88/100 — Solid configuration with a few gaps worth closing. Accepts mail · Protected against spoofing · Hosted by Microsoft 365
Findings
-
mx redundancy
Only one mail exchanger is published, so there is no failover.
github-com.mail.protection.outlook.com
Fix: Add a secondary MX at a higher priority number.
-
spf
SPF ends in ~all (softfail); unauthorised mail is marked rather than rejected.
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
Fix: Move to -all once you have confirmed all senders are listed.
-
mta sts
No MTA-STS policy, so inbound mail can be downgraded to an unencrypted connection.
Fix: Publish _mta-sts.github.com and host a policy at https://mta-sts.github.com/.well-known/mta-sts.txt.
-
mx
Mail is handled by Microsoft 365.
0 github-com.mail.protection.outlook.com
-
dmarc
DMARC is enforcing with p=quarantine.
v=DMARC1; p=quarantine; sp=reject; pct=100; rua=mailto:dmarc@github.com; ruf=mailto:dmarc@github.com; fo=1
-
dkim
DKIM keys found for 6 selectors.
google._domainkey, selector1._domainkey, k1._domainkey, k2._domainkey, s1._domainkey, s2._domainkey
Records
| MX | 0 github-com.mail.protection.outlook.com |
|---|---|
| SPF | 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 |
| DMARC | v=DMARC1; p=quarantine; sp=reject; pct=100; rua=mailto:dmarc@github.com; ruf=mailto:dmarc@github.com; fo=1 |
| DKIM selectors | google, selector1, k1, k2, s1, s2 |
| MTA-STS | not published |
| TLS-RPT | not published |
| BIMI | not published |
| DNSSEC | not validating |
Same data, as JSON, in one request. No SMTP probing, no stored recipient data, 250 free calls a month.
curl "https://mailgrade.dev/v1/domain?domain=github.com"
Also available: /v1/verify?email=… for individual addresses, and
/v1/verify/batch for lists.