Questions tagged [dkim]

DomainKeys Identified Mail is a scheme for signing and verifying email messages to confirm that that the source hasn't been forged, and is typically implemented by MTAs. The source MTA adds a header to the message body containing a signature, and the destination MTA verifies this signature against a key retrieved from DNS.

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How is this email passing DMARC?

Today we received a spoofed email: it was sent to us "from us". (Assume we own foo.com -- real domain redacted.) This is disturbing, as it shows as "from foo.com", yet the sender ...
Lawrence Wagerfield's user avatar
0 votes
1 answer
500 views

How do I add individual mail-sending websites to my SPF record?

My company, which sends @example.co email from Google Workspace, HubSpot, and Salesforce, has the following SPF record in DNS: v=spf1 include:_spf.google.com include:_spf.salesforce.com include:...
ST7686's user avatar
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1 vote
1 answer
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Added dkimproxy to OpenSMTPD ... mail loop when sending to my own domain

I have a nicely working OpenSMTPD configuration and I added dkimproxy to it. Everything is working nicely and mail-tester, etc., all report that I have proper DKIM signing and my email score is 10/10, ...
user227963's user avatar
2 votes
1 answer
1k views

Why do I get DMARC aggregate reports with no reported failures (G Suite + Amazon SES)?

Domain: franzoni.eu Such domain leverages G Suite (grandfathered free version) for receiving mail, but for various reasons (I prefer not to create users for M2M SMTP on G Suite, and I cannot use SMTP ...
Alan Franzoni's user avatar
6 votes
2 answers
4k views

Why does spf fail in DMARC report from Google?

I recently received a DMARC report from Google alerting me of a few SPF failures with mail originating from IP addresses belonging to Amazon SES. A sample record is as follows (I have replaced our ...
Leo Galleguillos's user avatar
0 votes
1 answer
3k views

Create a DKIM key to provide to a 3rd party so we can send as them?

We use o365/Exchange Online. All our SPF and DKIM configs are good for our domain (including 3rd party senders). Say we have a partner who has domain XYZ123.com (with their own mail servers) and they ...
techie007's user avatar
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Authorized domain in exchange 2010 would not send email to internet but internally to main domain

An authorized domain authorized-domain.tld in exchange 2010 with main domain main-domain.tld would not send email to internet but internally to main domain. Reproduced / describde scenario: User ...
Manifest Man's user avatar
5 votes
1 answer
9k views

1024 or 2048 bit keys for DKIM?

Referencing this: https://crypto.stackexchange.com/questions/72297/recommended-key-size-for-dkim What I get from this is (at the time) DNS providers (usually) allow for up to 1024 bit keys but not ...
Tyler Montney's user avatar
2 votes
1 answer
2k views

SpamAssassin: custom rules and score

For my mailserver, i want do add some custom rules and scores for spamasassin DKIM and SPF checks. Currently i use following custom settings: score DKIM_SIGNED 0 score DKIM_VALID -1 score ...
Tim Altgeld's user avatar
2 votes
0 answers
746 views

How to diagnose opendkim RSA signatures

I'm having an issue where my DKIM signatures are failing everywhere. There was a question on this here, but the original poster answered his own question, and the answer seems unrelated. After some ...
philolegein's user avatar
6 votes
1 answer
4k views

Mail from Teams forwarded to Gmail marked as spam due to DMARC failure

When I write a chat message in Microsoft Teams the receiver gets an e-mail notification on her Office 365 account ([email protected]) when she is offline in Teams. The receiver set it up so that all ...
Johannes Egger's user avatar
0 votes
1 answer
787 views

SPF/DKIM setup for a registrar's email forward

I have a number of domains with a registrar with straight forward forwards to another email address. The system has worked flawlessly for a lot of years over a lot of domains but recently I created a ...
Kevin_Wales's user avatar
2 votes
1 answer
3k views

Is DKIM/ARC working properly on my Mailman server?

I've set up a Mailman 3 server with Postfix. I've configured Postfix to add DKIM headers using OpenDKIM and a test email from that server to a Microsoft-hosted email address suggests that DKIM is OK: ...
Philip Colmer's user avatar
1 vote
1 answer
627 views

Amazon SES - Domain Verification Pending

I am trying to setup Amazon SES on my Route53 domain (writeurl.com). The domain verification status remains at pending verification and does not proceed. The following nslookup command does not show ...
Haris ur Rehman's user avatar
0 votes
2 answers
89 views

Doubts about DKIM verification (RFC6376)

Good morning, https://www.rfc-editor.org/rfc/rfc6376#section-5 reads: "Survivability of signatures after transit is not guaranteed, and signatures can fail to verify through no fault of the ...
Tom Johnson's user avatar
1 vote
1 answer
221 views

SPF/DKIM and sending emails from parent domain

I'm trying to understand how apps such as greenhouse.io configure DNS for delegating email sending. In short, assume I am a SAAS provider saas.com and my customer is customer.com. I've seen that it is ...
ragebiswas's user avatar
5 votes
1 answer
6k views

why is this DMARC failing verification?

I get a 6.1/10 score on mail-tester.com, where the DMARC verification is the only relevant penalty (-3). * Your DKIM signature is valid * Your message failed the DMARC verification A DMARC policy ...
Stuck's user avatar
  • 153
2 votes
0 answers
685 views

Google G Suite DMARC + SPF + DKIM for user domain aliases fail Google Admin Toolbox CheckMX

I have set up the above in my Google's old G-Suite account for a User Domain Alias but am still getting two warning messages: https://webcoder.co.uk There were some non-critical problems detected with ...
webcoder.co.uk's user avatar
2 votes
1 answer
565 views

Configuring DKIM using DNS and hosting on VPS

I'm using Mail Enable on my VPS and have copied the generated DKIM (see screenshot 1) to my DNS. (yes, I've restarted the VPS already): Now my DNS settings are configured at hosting company A, and ...
Adam's user avatar
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0 votes
0 answers
556 views

Incoming DKIM verfication check working but not rejecting

I have SPF, DMARC and DKIM configured for my mail server (postfix) on a CentOS 7 OS. Outgoing mail is getting signed as normal. All email check sites says my stuff are secured and working great but ...
iraqiboy90's user avatar
-1 votes
1 answer
120 views

Is it possible to host one TXT record for a domain on a different server, and leave all of the other DNS information intact on the first server?

I am running a business site on a computer with a managed hosting company. Everything is working fine, until I tried to establish DKIM verification for emails sent from the server. This required ...
user533604's user avatar
0 votes
2 answers
465 views

DKIM on subdomain hosted by domain.com, and auto-generated DKIM key

I've read a few different threads on here and have tried them out, but they don't seem to be working for me, so I'm hoping one of you awesome people can help me out. Forgive me, but this will be a ...
Brian Cook's user avatar
0 votes
1 answer
2k views

DMARC appears to fail, multiple DKIM signatures with one matching the from address

I am using a free outlook account. In the outlook account management portal I have added an alias for my custom domain ([email protected]). With this I am able to send mails from this alias, ...
Jorn Vanloofsvelt's user avatar
3 votes
1 answer
3k views

Sendmail authenticating with DKIM but Roundcube is not authenticating

So I have set up the mail server, Roundcube, and Sendmail both work as expected. but many of my emails were going to spam in Gmail and others, so I was setting up the DKIM auth and it was successful. [...
Ryan Vogel's user avatar
0 votes
0 answers
1k views

DMARC, DKIM, or SPF? Emails going into quarantine

I have never had to deal with DKIM, DMARC, or SPF records before; however, our SPF record is full (10, Cloudflare) and I have a vendor whose emails aren’t making it to our mailboxes. I made ...
Cody's user avatar
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0 votes
1 answer
123 views

DMARC report with passing O365 DKIM signature being sent by Google server

The dmarc report values are as follows: dkim_domain : mydomain.onmicrosoft.com dkim_result : pass selector : selector1-mydomain-onmicrosoft-com header_from : mydomain spf_domain : mydomain spf_result :...
Adam Winter's user avatar
1 vote
2 answers
2k views

How to get DKIM to sign for both, a subdomain and the root domain addresses?

I'm using latest versions of DKIM + Postfix on Ubuntu 20.04 I got the DKIM to sign the e-mails [email protected]. However it refuses to sign e-mails that originate from @mydomain.com. Is it ...
Mike's user avatar
  • 23
1 vote
1 answer
1k views

DKIM seems to be working but I get " dkim=temperror (no key for signature) "

DKIM with Postfix on Ubuntu 20.04 part of the e-mail header as it arrives at my google mail account: ARC-Authentication-Results: i=1; mx.google.com; dkim=temperror (no key for signature) header....
Mike's user avatar
  • 23
6 votes
1 answer
2k views

No DKIM headers in sent mails from postfix

I have two postfix, one for receiving mails and the other for sending mails, and I am having trouble signing dkim on my outgoing mails. I followed this tutorial. Logs also is not helping me point to ...
user13539846's user avatar
-1 votes
1 answer
2k views

How can I enable DKIM email verification on windows server 2019 for sending DKIM verified email via SMTP service?

I am sending activation and verification emails from my domain : https://www.monstermmorpg.com/ Recently I have moved to a new installation The new server is : Windows Server 2019 How can I set a ...
Furkan Gözükara's user avatar
1 vote
0 answers
193 views

DKIM with Exim4 on Debian "Buster"

Can anybody confirm please that in order to get DKIM working the exim4-lite package still has to be replaced with exim4-heavy? If so, what is the correct sequence? Something like apt-get purge exim4-...
Mark Morgan Lloyd's user avatar
0 votes
1 answer
180 views

Send each email from a different subdomain?

There are clearly benefits of using a subdomain for sending email to protection domain reputation, but is this always true? What about the extreme case, where a spam domain sends every email from a ...
rosstex's user avatar
  • 133
0 votes
1 answer
413 views

DKIM Record Not Working

I was setup SPF, DKIM and DMARC Record for my mail server, SPF and DMARC Record are working normally now, But i got a problem for my DKIM Record, When i do: dig default._domainkey.example.com txt The ...
user649109's user avatar
0 votes
0 answers
368 views

DKIM validation fails only on Outlook

I'm configuring OpenDKIM to sign miltiple domains with the same key on Pstfix. I followed this tutorial with s=mail and d=example.com. SigningTable: * mail._domainkey.example.com KeyTable: ...
Demba's user avatar
  • 11
1 vote
1 answer
788 views

DKIM signing for subdomain issue

I am in an environment that sends emails from different sources. We're a Google Workspace environment as well. The flow is as such: A user ([email protected]) in Gmail sends an email to an email group (...
Phyxiis's user avatar
  • 11
0 votes
2 answers
195 views

Postfix can't receive external mails since TLS has been set up

I have a postfix mail server with which I am able to : send mails (to google for example) with the commande : "echo foo | mail -s 'bar' [email protected]" send mails with php mail() send and ...
Mr Bricole's user avatar
25 votes
5 answers
7k views

Does DKIM alone not solve the spam issue? Why do I need SPF?

FINAL EDIT : I was completely wrong about DKIM it seems, the signing domain does not have to be the same as the sender domain, thus the whole premise for my question is flawed. A lot of thanks to Paul ...
cornergraf's user avatar
1 vote
1 answer
699 views

Mistake with DKIM 9936A801ED08: no signing table match for using wildcard

I have configured DKIM to be used with wildcards in SigningTable (Centos7) But it gives me an error, and I am not able to see it. Feb 15 08:46:56 monitor01 postfix/submission/smtpd[3374]: connect from ...
abkrim's user avatar
  • 416
0 votes
1 answer
1k views

Failing DKIM when sending postfix email

I set up a postfix/dovecot server. My ISP blocks outbound port 25, so I use an SMTP relay (mailjet). When I send an email to gmail, it ends up in the "promotions" category which is ...
Stewart's user avatar
  • 351
0 votes
1 answer
95 views

Is everything OK based on this DMARC report?

Do I understand it correct that everything is OK and I have both SPF and DKIM configured correctly based on this report from Google? <?xml version="1.0" encoding="UTF-8" ?> &...
IvanD's user avatar
  • 103
9 votes
1 answer
11k views

opendkim-testkey: key not secure

I set up Opendkim milter to work with postfix on my machine. Now email is signed & verified correctly i.e. email source code shows DKIM-Signature header. TXT record on the authorative dns is set ...
71GA's user avatar
  • 383
0 votes
1 answer
780 views

DKIM - key pair generation recommendations

I wonder if it is okay to generate a key pair (.key and .cert files) for DKIM like this: openssl req -newkey rsa:2048 -sha256 -x509 -nodes -days 3650 -keyout dkim-rsa.key -out dkim-rsa.cert By ...
71GA's user avatar
  • 383
0 votes
1 answer
343 views

Would adding CNAME records in DNS server for setting up DKIM cause email server issues?

I want to add two CNAME records to make my Microsoft exchange be DKIM compliant according to Microsoft.com’s instructions. Is there any possibility adding the two CNAME records would cause disruptions ...
Coo's user avatar
  • 103
2 votes
2 answers
631 views

Will DKIM cause unsigned messages to bounce?

If DKIM has been configured on a domain (DNS has a TXT record containing a DomainKey), is it necessary to sign all outgoing messages, or is it optional? I have a domain with a corporate mail server ...
Matt's user avatar
  • 75
5 votes
1 answer
593 views

Is email deliverability impossible with a .name email address?

I have a dot name domain. .name is an odd TLD: they originally only offered third level domains, eg first.last.name, so that more people could get their own name. They also included the first@last....
ryan's user avatar
  • 281
0 votes
1 answer
116 views

System to prove content of a DNS record/DKIM key at a certain time?

I'm trying to build a way to prove that an e-mail was indeed sent from a specific domain. Is there a service that allows me to demonstrate what value a TXT record had at a certain time, e.g. by ...
Jan Schejbal's user avatar
0 votes
1 answer
1k views

DKIM and subdomains

We use a sub domain "mail.domain.com" for sending marketing emails from Salesforce Marketing Cloud, the reason it was set up this way is to keep the reputation of this domain separate from ...
Oliver Brayshaw's user avatar
1 vote
1 answer
3k views

Forward messages to Gmail (postfix+SRS) has DMARC failure even though SPF and DKIM succeed

I run my own domain, but forward many email addresses to my gmail account. Recently, I started seeing a lot of messages marked by gmail as spam. I have SPF set for my outgoing email, and use SRS to ...
Mikeage's user avatar
  • 2,741
6 votes
2 answers
6k views

DMARC fail, but DKIM and SPF are passing

I am using AWS SES (in sandbox mode) to send an email to a GMail address. Unfortunately it gets flagged as spam. Google is nice enough to tell me in the message details that it is a DMARC failure I ...
YannP's user avatar
  • 183
1 vote
1 answer
2k views

Windows DNS and long DKIM keys

One of our third party services that we sends as provided us with a DKIM record that is longer than 255 characters and they won't provide a shorter one. How do I properly use what they've provided ...
kausner's user avatar
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