Mail domain report: lynda.com

SPF

pass

SPF record published

Found

Record: v=spf1 ip4:216.84.189.0/24 ip4:64.18.0.0/20 ip4:91.143.106.55 ip4:107.21.2.3 a:zgateway.zuora.com include:_spf.google.com include:mktomail.com include:_spf1.lynda.com include:linkedin.com ~all
DNS lookups: 7 of 10
Void lookups: 0 of 2

Checks

✓ No deprecated ptr mechanism #1

No ptr mechanism found in SPF record.
✓ 7 of 10 DNS lookups #2

SPF record needs 7 DNS lookups (limit is 10).
✓ Ends with ~all #3

SPF record properly uses ~all to restrict unauthorized senders.
✓ Record published #6

SPF record exists for this domain.
✓ Single record #16

Exactly one SPF record is published.
✓ Valid syntax #25

All SPF mechanisms and modifiers are valid.
✓ No void lookups #26

All include/redirect targets exist.
✓ No overly broad IP ranges #27

All ip4/ip6 ranges are narrow enough.

DMARC

pass

p=reject (_dmarc.lynda.com)

Found

Record: v=DMARC1; p=reject; rua=mailto:linkedin@rua.agari.com; ruf=mailto:linkedin@ruf.agari.com
Found at: _dmarc.lynda.com
External report address: mailto:linkedin@rua.agari.com (authorized)
External report address: mailto:linkedin@ruf.agari.com (authorized)

Tag	Value	Meaning
v	DMARC1	Version
p	reject	Policy
rua	mailto:linkedin@rua.agari.com	Aggregate report addresses
ruf	mailto:linkedin@ruf.agari.com	Failure report addresses

Checks

✓ Policy: reject #4

DMARC policy is set to 'reject', which provides the strongest protection against email spoofing.
✓ Record published #5

DMARC record exists for this domain.
✓ Valid syntax #17

DMARC record syntax is valid.
✓ Applies to 100% of mail #18

DMARC policy applies to all failing mail.
✓ Aggregate reports enabled #19

Aggregate reports are sent to: mailto:linkedin@rua.agari.com
✓ Subdomain policy: reject #20

Subdomains are covered by policy 'reject'.
✓ External report addresses authorized #29

Report addresses in other domains have published their authorization.

DKIM

warn

Selectors: google

Found

Selectors: google
_domainkey: NOERROR

Selector	Key	Flags
google	RSA 1024 bits

Checks

✓ Keys found: google #7

DKIM keys found for this domain with selectors: google
!

1024-bit DKIM key

1024-bit RSA keys are the minimum and are considered weak today: google (1024 bits). Rotate to a 2048-bit key.

#23
✓ No problematic flags #24

No keys in test mode, revoked, or limited to SHA-1.

DNSSEC

warn

Not signed

Found

DNSKEY records: No (0)
DS at parent: No

Checks

!

Not enabled

DNSSEC is not enabled for this domain. Consider enabling DNSSEC to protect against DNS spoofing attacks.

#8

MX

warn

6 mail servers

Found

Priority	Host	Records	Reverse DNS
10	mail-1.linkedin.com	A 108.174.0.93 AAAA 2620:119:50c0:207::5d	mail-1.linkedin.com ✓ mail-1.linkedin.com ✓
15	mail-2.linkedin.com	A 108.174.3.93 AAAA 2620:109:c006:104::5d	mail-2.linkedin.com ✓ mail-2.linkedin.com ✓
15	mail-d.linkedin.com	A 108.174.6.215 AAAA 2620:109:c003:104::215	mail-d.linkedin.com ✓ mail-d.linkedin.com ✓
20	mail-a.linkedin.com	A 108.174.0.215 AAAA 2620:119:50c0:207::215	mail-a.linkedin.com ✓ mail-a.linkedin.com ✓
20	mail-c.linkedin.com	A 108.174.3.215 AAAA 2620:109:c006:104::215	mail-c.linkedin.com ✓ mail-c.linkedin.com ✓
20	mail.linkedin.com	A 108.174.6.215 A 108.174.3.215 A 108.174.0.215	mail-d.linkedin.com ✓ mail-c.linkedin.com ✓ mail-a.linkedin.com ✓

Checks

✓ 6 MX records #9

Found 6 MX records for this domain.
✓ All hosts resolve #10

All MX records resolve to valid IP addresses.
!

Hosts without IPv6

The following MX hosts could not be resolved to IPv6 addresses: mail.linkedin.com

#11
✓ Redundant MX hosts #12

Found 6 MX records, which provides redundancy for email delivery.
!

More than 5 MX records

Found 6 MX records, which is more than the recommended maximum of 5. Too many MX records may indicate a misconfiguration.

#13
✓ No localhost targets #14

No MX records pointing to localhost found.
✓ No private IP addresses #15

No MX records resolving to private IP addresses found.
✓ No CNAME targets #22

No MX records point to a CNAME.
✓ Reverse DNS confirmed #30

All 13 MX addresss have a PTR record that resolves back to them.

TLS

warn

no MTA-STS · no TLS-RPT · DANE on 0 of 6 MX hosts

Found

DANE (TLSA records)

MX host	TLSA	DNSSEC
mail-1.linkedin.com	none	-
mail-2.linkedin.com	none	-
mail-d.linkedin.com	none	-
mail-a.linkedin.com	none	-
mail-c.linkedin.com	none	-
mail.linkedin.com	none	-

Checks

!

Not configured

MTA-STS is not configured, so other mail servers fall back to unencrypted delivery when TLS fails or is stripped by an attacker. Publish a _mta-sts TXT record and a policy at https://mta-sts.<domain>/.well-known/mta-sts.txt.

#32
i

Not configured

TLS-RPT lets senders report TLS delivery problems to you. It is most useful together with MTA-STS or DANE.

#35
i

Not used

No MX host publishes TLSA records. DANE lets senders verify your mail server's certificate through DNSSEC; it requires DNSSEC on the MX host's zone.

#36

BIMI

info

No BIMI record

Checks

i

Not configured

BIMI shows your logo next to your mail in supporting mail clients. It requires DMARC enforcement.

#38