4B

4-b.ch

Industry: Building materials
Headquarters: Hochdorf, Lucerne
Type: private
Employees (approx.): 600
Checked on: 19 October 2026

55/100Grade C

Protection against forged senders: not protected

Points per criterion

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

Industry avg.: 60.3 ▼ 5.3
Canton avg.: 56.6 ▼ 1.6
Overall avg.: 53.5 ▲ 1.5
Rank 12 of 20 in the industry

Findings

✕No DMARC record

Without DMARC no receiver reliably rejects forged mail in the domain's name, and the organisation receives no abuse reports.
!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.
!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 · 4B AG
Tenant region: EU

Signals (8)

SPF	Microsoft 365	`include:spf.protection.outlook.com`
DKIM	Microsoft 365	`selector1 → selector1-4b-ch0c._domainkey.4bfensterag.onmicrosoft.com`
Autodiscover	Microsoft 365	`autodiscover.outlook.com`
Domain verification	Microsoft 365	`MS=ms26208561`
Network	Microsoft 365	`AS8075 MICROSOFT-CORP-MSN-AS-BLOCK - Microsoft Corporation`
Domain verification	Google Workspace	`google-site-verification=qS50S0dNd2yJq9l`
SPF	Swiss hoster	`include:spf.hostpoint.ch`
Entra ID	Microsoft 365	`Entra-ID-Tenant (Managed)`

MX servers

Pref	Host	IP	Network	Country	TLSA
5	`4b-ch0c.mail.eo.outlook.com`	`52.101.68.27`	AS8075 MICROSOFT-CORP-MSN-AS-BLOCK - Microsoft Corporation	US	–
		`52.101.181.156`	AS8075 MICROSOFT-CORP-MSN-AS-BLOCK - Microsoft Corporation	US
		`52.101.209.153`	AS8075 MICROSOFT-CORP-MSN-AS-BLOCK - Microsoft Corporation	US

SPF

v=spf1 a:lx49.hoststar.hosting ip4:193.246.23.205 ip4:193.246.23.196 ip4:80.74.153.0/24 include:_spf.zimpel.de include:_spf.rexx-systems.com include:_spf.rexx-suite.com include:spf.protection.outlook.com include:Servers.mcsv.net include:relay.mailchannels.net redirect=spf.hostpoint.ch

all: -all
DNS lookups: 8 / 10
Includes: _spf.zimpel.de_spf.rexx-systems.com_spf.rexx-suite.comspf.protection.outlook.comservers.mcsv.netrelay.mailchannels.netspf.hostpoint.ch
Detected sending services: Microsoft 365, Mailchimp/Mandrill, Hostpoint
IPv4: 262 addresses authorised directly

DMARC

Without DMARC no receiver reliably rejects forged mail in the domain's name, and the organisation receives no abuse reports.

DKIM

Selector	Key	delegated to
`k2`	RSA 2048	`dkim2.mcsv.net`
`k3`	RSA 2048	`dkim3.mcsv.net`
`selector1`	RSA 1024	`selector1-4b-ch0c._domainkey.4bfensterag.onmicrosoft.com`

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

Transport encryption

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

Verified services

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

Microsoft 365GoogleApple

History

19 October 2026 Score 55 · DMARC -

All changes of this organisation in the change log →

Raw data

4-b.ch. IN MX 5 4b-ch0c.mail.eo.outlook.com.
4-b.ch. IN TXT "v=spf1 a:lx49.hoststar.hosting ip4:193.246.23.205 ip4:193.246.23.196 ip4:80.74.153.0/24 include:_spf.zimpel.de include:_spf.rexx-systems.com include:_spf.rexx-suite.com include:spf.protection.outlook.com include:Servers.mcsv.net include:relay.mailchannels.net redirect=spf.hostpoint.ch"

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