Goldbach

goldbach.com

Industry: Telecom, IT & media
Headquarters: Küsnacht, Zurich
Type: private
Employees (approx.): 700
Checked on: 19 October 2026

64/100Grade C

Protection against forged senders: largely protected

Points per criterion

MX 10 / 10
SPF 15 / 15
DKIM 20 / 20
DMARC 19 / 25
DNSSEC 0 / 10
Transport (MTA-STS/DANE) 0 / 15
TLS-RPT 0 / 5

Industry avg.: 63.6 ▲ 0.4
Canton avg.: 53 ▲ 11
Overall avg.: 53.5 ▲ 10.5
Rank 26 of 50 in the industry

Findings

!SPF close to the 10-lookup limit (8)

One more sending service can break the limit. Flattening or subdomains for third parties create headroom.
!DKIM key below 2048 bits

RSA-1024 is considered too weak (RFC 8301, M3AAWG). Rotate to 2048-bit keys.
!DNSSEC not enabled

Without DNSSEC, DNS answers can be forged in transit. DANE requires DNSSEC.
!No MTA-STS

Without MTA-STS (or DANE) inbound encryption is not enforced; an attacker on the path can downgrade to plain text.
!No TLS reporting (TLS-RPT)

Without TLS-RPT the organisation does not learn when senders fail to deliver encrypted.

Check live in the Mail DNS Check →

Who runs the mail?

Mailbox provider: Microsoft 365
Provider jurisdiction: USA · MX: US
Detection confidence: 100 / 100
Microsoft tenant: Federated · Goldbach Group AG
Tenant region: EU
Federated via: login.tx.group

Signals (10)

MX	Microsoft 365	`goldbach-com.q-v1.mx.microsoft`
SPF	Microsoft 365	`include:spf.protection.outlook.com`
DKIM	Microsoft 365	`selector1 → selector1-goldbach-com._domainkey.goldbach.onmicrosoft.com`
Autodiscover	Microsoft 365	`autodiscover.outlook.com`
Domain verification	Microsoft 365	`MS=ms60528305`
Network	Microsoft 365	`AS8075 MICROSOFT-CORP-MSN-AS-BLOCK - Microsoft Corporation`
SPF	Google Workspace	`include:_spf.google.com`
DKIM	Google Workspace	`google`
Domain verification	Google Workspace	`google-site-verification=uLshE_P2FoDD1c9`
Entra ID	Microsoft 365	`Entra-ID-Tenant (Federated)`

MX servers

Pref	Host	IP	Network	Country	TLSA
0	`goldbach-com.q-v1.mx.microsoft`	`52.101.103.140`	AS8075 MICROSOFT-CORP-MSN-AS-BLOCK - Microsoft Corporation	US	–
		`52.101.73.123`	AS8075 MICROSOFT-CORP-MSN-AS-BLOCK - Microsoft Corporation	US
		`52.101.68.10`	AS8075 MICROSOFT-CORP-MSN-AS-BLOCK - Microsoft Corporation	US

SPF

v=spf1 include:_spf.google.com include:spf.protection.outlook.com include:_spf.salesforce.com include:eu.mailgun.org include:sendgrid.net -all

all: -all
DNS lookups: 8 / 10
Includes: _spf.google.comspf.protection.outlook.com_spf.salesforce.comeu.mailgun.orgsendgrid.net
Detected sending services: Google, Microsoft 365, Salesforce, Mailgun, SendGrid

DMARC

v=DMARC1; p=quarantine; rua=mailto:i5xs0ljo@rua.eu.dmarcmanager.app,mailto:4y8d7eqyys@rua.powerdmarc.com; ruf=mailto:i5xs0ljo@ruf.eu.dmarcmanager.app,mailto:4y8d7eqyys@ruf.powerdmarc.com; fo=1

Policy: p=quarantine
Subdomains (sp): inherits p=quarantine
Share (pct): 100 %
Alignment DKIM/SPF: relaxed / relaxed
Aggregate reports (rua): i5xs0ljo@rua.eu.dmarcmanager.app4y8d7eqyys@rua.powerdmarc.com
Forensic reports (ruf): i5xs0ljo@ruf.eu.dmarcmanager.app4y8d7eqyys@ruf.powerdmarc.com
Report services: PowerDMARC

DKIM

Selector	Key	delegated to
`google`	RSA 1024	–
`s1`	RSA 2048	`s1.domainkey.u46969590.wl091.sendgrid.net`
`s2`	RSA 2048	`s2.domainkey.u46969590.wl091.sendgrid.net`
`selector1`	RSA 1024	`selector1-goldbach-com._domainkey.goldbach.onmicrosoft.com`
`selector2`	RSA 1024	`selector2-goldbach-com._domainkey.goldbach.onmicrosoft.com`

Checked: 100 common selectors. Keys under custom selectors remain invisible.

Transport encryption

MTA-STS: missing
DANE: missing
DNSSEC: missing
TLS-RPT: missing
BIMI: missing

Verified services

From verification records in the domain TXT: services where the domain is verified.

Microsoft 365GoogleAppleAtlassianDocuSignZoomMiroAirtablePostman

History

18 October 2026 Score 64 · DMARC quarantine

All changes of this organisation in the change log →

Raw data

goldbach.com. IN MX 0 goldbach-com.q-v1.mx.microsoft.
goldbach.com. IN TXT "v=spf1 include:_spf.google.com include:spf.protection.outlook.com include:_spf.salesforce.com include:eu.mailgun.org include:sendgrid.net -all"
_dmarc.goldbach.com. IN TXT "v=DMARC1; p=quarantine; rua=mailto:i5xs0ljo@rua.eu.dmarcmanager.app,mailto:4y8d7eqyys@rua.powerdmarc.com; ruf=mailto:i5xs0ljo@ruf.eu.dmarcmanager.app,mailto:4y8d7eqyys@ruf.powerdmarc.com; fo=1"

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