Zühlke

zuehlke.com

Industry: Telecom, IT & media
Headquarters: Schlieren, Zurich
Type: private
Employees (approx.): 2,000
Checked on: 19 October 2026

70/100Grade B

Protection against forged senders: protected

Points per criterion

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

Industry avg.: 63.6 ▲ 6.4
Canton avg.: 53 ▲ 17
Overall avg.: 53.5 ▲ 16.5
Rank 19 of 50 in the industry

Findings

!SPF close to the 10-lookup limit (9)

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: Managed · Zühlke Engineering AG
Tenant region: EU

Signals (8)

MX	Microsoft 365	`zuehlke-com.mail.protection.outlook.com`
SPF	Microsoft 365	`include:spf.protection.outlook.com`
DKIM	Microsoft 365	`selector2 → selector2-zuehlke-com._domainkey.zuhlke.onmicrosoft.com`
Autodiscover	Microsoft 365	`autodiscover.outlook.com`
Network	Microsoft 365	`AS8075 MICROSOFT-CORP-MSN-AS-BLOCK - Microsoft Corporation`
Domain verification	Google Workspace	`google-site-verification=t0LX3qPikX-ydXG`
SPF	Amazon	`include:amazonses.com`
Entra ID	Microsoft 365	`Entra-ID-Tenant (Managed)`

MX servers

Pref	Host	IP	Network	Country	TLSA
10	`zuehlke-com.mail.protection.outlook.com`	`52.101.103.162`	AS8075 MICROSOFT-CORP-MSN-AS-BLOCK - Microsoft Corporation	US	–
		`52.101.181.153`	AS8075 MICROSOFT-CORP-MSN-AS-BLOCK - Microsoft Corporation	US
		`52.101.103.39`	AS8075 MICROSOFT-CORP-MSN-AS-BLOCK - Microsoft Corporation	US

SPF

v=spf1 mx include:spf.amazee.io include:spf.protection.outlook.com include:spf.nl2go.com include:_spf.atlassian.net ip4:193.135.254.84 ip4:185.69.92.248 ip4:136.243.173.218 ip4:193.169.180.64 ip4:151.101.2.191 ip4:151.101.66.191 ip4:151.101.130.191 ip4:151.101.194.191 -all

all: -all
DNS lookups: 9 / 10
Includes: spf.amazee.iospf.protection.outlook.comspf.nl2go.com_spf.atlassian.net
Detected sending services: Microsoft 365, Atlassian, Amazon SES
IPv4: 8 addresses authorised directly

DMARC

v=DMARC1; p=reject; pct=100; rua=mailto:lfsdkzit@ag.eu.dmarcian.com, mailto:operator@zuehlke.com; ruf=mailto:operator@zuehlke.com

Policy: p=reject
Subdomains (sp): inherits p=reject
Share (pct): 100 %
Alignment DKIM/SPF: relaxed / relaxed
Aggregate reports (rua): lfsdkzit@ag.eu.dmarcian.comoperator@zuehlke.com
Forensic reports (ruf): operator@zuehlke.com
Report services: dmarcian

DKIM

Selector	Key	delegated to
`s1`	RSA 2048	`s1.domainkey.u16276103.wl104.sendgrid.net`
`s2`	RSA 1024	`s2.domainkey.u16276103.wl104.sendgrid.net`
`selector2`	RSA 1024	`selector2-zuehlke-com._domainkey.zuhlke.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.

GoogleMeta/FacebookAtlassianMiro

History

18 October 2026 Score 70 · DMARC reject

All changes of this organisation in the change log →

Raw data

zuehlke.com. IN MX 10 zuehlke-com.mail.protection.outlook.com.
zuehlke.com. IN TXT "v=spf1 mx include:spf.amazee.io include:spf.protection.outlook.com include:spf.nl2go.com include:_spf.atlassian.net ip4:193.135.254.84 ip4:185.69.92.248 ip4:136.243.173.218 ip4:193.169.180.64 ip4:151.101.2.191 ip4:151.101.66.191 ip4:151.101.130.191 ip4:151.101.194.191 -all"
_dmarc.zuehlke.com. IN TXT "v=DMARC1; p=reject; pct=100; rua=mailto:lfsdkzit@ag.eu.dmarcian.com, mailto:operator@zuehlke.com; ruf=mailto:operator@zuehlke.com"

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