Rafael Pfister
+41 58 510 22 08 Consulting

Gruner

gruner.ch

Industry
Construction & real estate
Headquarters
Basel, Basel-City
Type
private
Employees (approx.)
1,500
Checked on
19 October 2026
36/100Grade D

Protection against forged senders: not protected (monitoring only)

Points per criterion

  • MX 10 / 10
  • SPF 0 / 15
  • DKIM 20 / 20
  • DMARC 6 / 25
  • DNSSEC 0 / 10
  • Transport (MTA-STS/DANE) 0 / 15
  • TLS-RPT 0 / 5

Findings

  • ✕SPF exceeds 10 DNS lookups (13)

    More than ten lookups (include, a, mx, ptr, exists, redirect) cause a permerror; many receivers then treat SPF as failed.

  • ✕DMARC in monitoring mode only (p=none)

    p=none provides reports but does not reject a single forgery. The goal is p=reject.

  • !SPF contains void includes (1)

    At least one include points to a domain without SPF. Usually a leftover of a retired service; it can cause a permerror.

  • !DMARC without reporting (no rua)

    Without aggregate reports it stays invisible who sends in the domain's name.

  • !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 · Gruner AG
Tenant region
EU
Signals (7)
MXMicrosoft 365gruner-ch.mail.protection.outlook.com
SPFMicrosoft 365include:spf.protection.outlook.com
DKIMMicrosoft 365selector1 → selector1-gruner-ch._domainkey.gruner.onmicrosoft.com
AutodiscoverMicrosoft 365autodiscover.outlook.com
NetworkMicrosoft 365AS8075 MICROSOFT-CORP-MSN-AS-BLOCK - Microsoft Corporation
SPFSwiss hosterinclude:_spf.v4.hosttech.eu
Entra IDMicrosoft 365Entra-ID-Tenant (Managed)

MX servers

PrefHostIPNetworkCountryTLSA
0 gruner-ch.mail.protection.outlook.com 52.101.73.123 AS8075 MICROSOFT-CORP-MSN-AS-BLOCK - Microsoft Corporation US –
52.101.73.145 AS8075 MICROSOFT-CORP-MSN-AS-BLOCK - Microsoft Corporation US
52.101.185.21 AS8075 MICROSOFT-CORP-MSN-AS-BLOCK - Microsoft Corporation US

SPF

v=spf1 include:spf.protection.outlook.com include:spf.mailxpert.ch include:spf01.eyecatcher.ch include:spf.nextron.ch include:include:spf.umantis.com include:spfv4.sosafe.de include:spfv6.sosafe.de ip4:193.142.157.173 -all
all
-all
DNS lookups
13 / 10
Includes
spf.protection.outlook.comspf.mailxpert.chspf01.eyecatcher.chspf.nextron.chinclude:spf.umantis.comspfv4.sosafe.despfv6.sosafe.de
Detected sending services
Microsoft 365, Mailxpert
IPv4
1 addresses authorised directly

DMARC

v=DMARC1;p=none;pct=100;sp=none
Policy
p=none
Subdomains (sp)
none
Share (pct)
100 %
Alignment DKIM/SPF
relaxed / relaxed
Aggregate reports (rua)
–

DKIM

SelectorKeydelegated to
mail RSA 1024 –
selector1 RSA 1024 selector1-gruner-ch._domainkey.gruner.onmicrosoft.com
selector2 RSA 2048 selector2-gruner-ch._domainkey.gruner.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.

Brevo

History

  • Score 36 · DMARC none

All changes of this organisation in the change log →

Raw data 
gruner.ch. IN MX 0 gruner-ch.mail.protection.outlook.com.
gruner.ch. IN TXT "v=spf1 include:spf.protection.outlook.com include:spf.mailxpert.ch include:spf01.eyecatcher.ch include:spf.nextron.ch include:include:spf.umantis.com include:spfv4.sosafe.de include:spfv6.sosafe.de ip4:193.142.157.173 -all"
_dmarc.gruner.ch. IN TXT "v=DMARC1;p=none;pct=100;sp=none"

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