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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25 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 ...
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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 ...
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BlackList UCEPROTECTL3 Policy for e-mail? [closed]

Not sure that this is the correct forum for this, but it is kind of interesting because it took about an hour to figure out what the real problem is. More of a discussion, but also asking for ...
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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: ...
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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 (test@domain.tld) in Gmail sends an email to an email group (...
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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' mail@gmail.com" send mails with php mail() send and ...
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DKIM verification for emails sent from another domain using main domain

Say, I have two domains. maildomain.com and vhost.com. Both are hosted in different server thus have separate IP. Both have their own DKIM, SPF and DMARC records set up properly. Now, if I send ...
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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 ...
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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 ...
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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 ...
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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" ?> &...
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OpenSMTPD and Rspamd won't sign my emails

I host a OpenBSD machine with a mail server and recently started noticing that Google is mailing me on a daily basis because my e-mails are not passing the DKIM test which I tested and worked in the ...
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732 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 ...
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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 ...
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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 ...
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1answer
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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 ...
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1answer
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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....
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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 ...
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111 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 ...
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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 ...
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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 ...
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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 ...
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DKIM and multiple Email protection Gateways

Just wondering if anyone has ever setup DKIM with multiple email protection gateways We are running with 365 and a couple of email protection gateways in front Do you need to add the public key to ...
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1answer
141 views

Exim unable to sign DKIM keys for outgoing mail

I currently have an issue with exim, I am trying to make it so it will sign outgoing emails for specific domains with a key for DKIM (there are multiple domains that this server sends for and not all ...
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1answer
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How to set Public Key DKIM in Postfix

I need to set up my public key in the postfix server, I already generated the keys in https://dkimcore.org/tools/, and added the TXT records in my DNS provider. But I have no idea how to set it in my ...
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Email protected with SPF but received valid signature from other IP anyway

I've received an email in spam from info@mydomain.com to info@mydomain.com, but the "sent by" came from rec15.appleandrdoidmail.mx. info@mydomain.com is an alias. Weird thing is that it says ...
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1answer
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OpenDKIM not signing but no error

I've set up opendkim (2.10) with postfix on an ubuntu 16.04 host. According to the logs, all is fine (i.e., no errors), but mail isn't being signed. I can see that postfix is passing messages to ...
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250 views

DKIM Key Rotation Best Practices

Do you find it necessary to regenerate your DKIM keys every 1-6 months to avoid your mail going into the receiving servers' junk mail folder? Some guides recommend this, some even say it's "Best ...
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241 views

intermittent DKIM failure

We have several email servers that send out legitmate email via PostFix and use openDKIM. Recently we've had some recievers claim the DKIM record can not be verified so we've tried various tools such ...
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1answer
101 views

DKIM aligned but not authenticated on On-Premises Exchange 2019

I have an On-Premises Exchange 2019 server with Hybrid Deployment with Office365 configured. Everything is working as expected, but DKIM aligned messages are arriving as unauthenticated. I can confirm ...
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Issue with opendkim key not valid in dns check

I am checking the dkim key generated by opendkim and I keep getting an error of key not valid. Here is the output of mail.txt key file: I replaced my domain with example.com in this scenario. mail....
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Is it possible to use JavaMail with DKIM when sending from Domain Alias (G Suite)?

My understanding is G Suite SMTP feature is only for primary domain and not domain alias. The SMTP configuration in G Suite admin console are mainly for primary domain. Assuming that DKIM is ...
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record DKIM on IONOS makes sense?

If I am sending mail through SMTP, I understand that it is IONOS who signs those emails, right? I would like to add the DKIM header to my emails. I know that it is necessary to publish a CNAME record ...
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SPF and DKIM for one domain on two servers [closed]

I followed this guide to setup SPF and DKIM for emails to be sent from a server for a domain. That server is the location of the actual email server for the domain. I now want to setup another server ...
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1answer
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Modifying date breaks DKIM signature. Alternatives?

On our Postfix server we previously removed the Date header from incoming emails and had Postfix automatically add it again to prevent spoofing the date and to work around mail servers with off clocks....
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940 views

emails to Yahoo are ending up in SPAM folder despite spf=pass, dkim=pass and dmarc=pass

Are we possibility having a reputation problems with Yahoo emails? Yahoo raw mail header finds my policy I published: dmarc=success(p=REJECT,sp=REJECT) Emails to clients at Google and Outlook are not ...
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Why is opendmarc SPF failing this arriving message?

Why is this incoming message failing? postfix/smtpd[4776]: connect from mail-mw2nam10on2073.outbound.protection.outlook.com[40.107.94.73] postfix/smtpd[4776]: Anonymous TLS connection established ...
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140 views

All mails to Yahoo are deferred or in spam

i have read a lot about the problems of delivering mail to yahoo.com, i have contact the tech support but the result it's always the same: from my server all mails to yahoo./aol. are deffered and when ...
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Correct DKIM, Reverse DNS configuration to send from 2 different domains?

I have set up Postfix on an Ubuntu 18.04, with a view to sending emails from two different domains, which I will refer to here as abc.com and xyz.com. I'm trying to configure everything so that emails ...
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VERP: rewrite from header of NDR?

We provide cmail delivery for external clients from several different domains. We rewrite the envelope sender (AKA: "SMTP MAIL FROM","Return-Path" ) using a form of VERP. Thus we ...
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1answer
208 views

Is SPF alignment important with DMARC?

When setting up a DMARC policy for an organization, is it important at all to have SPF alignment? I've gathered that: Most email service providers support DKIM for a custom domain. Not all email ...
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Is ed25519 well supported for the DKIM validation?

Based on the Exim4 docs I have the following script: #! /bin/bash -- ED="dkim_ed25519_$(date +'%Y%m%d')" RSA="dkim_rsa_$(date +'%Y%m%d')" ## Generate private key openssl genpkey -...
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Exim: DKIM: signing failed: PRIVKEY

Does anyone know what this error message means and how to fix it? Every time I send an email, I get the following messages in /var/log/exim4/paniclog: signing_init: privkey PEM-block import: The ...
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1answer
71 views

Postfix send mail only to GMail, all other domains are deferred and not sended

My Postfix server is running on Debian Stretch. It is able to send emails to a GMail address without problems which are not considered as spam. At the DNS level I configured DKIM, SPF and DMARC and ...
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128 views

How can I fix emails being marked as spam after being edited by Postfix?

Recently, I set up a Linux server running Postfix that I'm using to send and relay emails. I've also set up an email address that's used as an alias and forwards the emails to another email address, ...
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Exim4 not signing my Email, even after setting up the split config

I already try anything that I could. I use exim on ubuntu/debian based, and using split config, and this's the config DKIM_CANON = relaxed DKIM_SELECTOR = mail # Get the domain from the outgoing mail....
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139 views

Emails not adding DKIM signature: Milter service - Connection refused [closed]

I have generated and added a DKIM record with a selector: 2020. The DKIM record seems to have been added successfully when I used a few DKIM checkers online but GMAIL (mailed-by is displayed whereas ...
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1answer
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Can I DKIM sign my email without running a server daemon just for that?

I have an email server that is working perfectly. However, more and more other email servers are getting strict about DKIM signing and DMARC records so I guess I need to finally set that up ... I am ...
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1answer
138 views

How to resolve “signing key too small” issue from mail-tester

We've recently been having some email delivery issues, so I find myself taking my first dive into the email server set-up world to make sure our emails are arriving as expected. I ran mail-tester a ...
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98 views

Change From (Sender) address using Postfix as a relay and pass validation

I'm trying to relay mail via Postfix and change the sender address whilst also passing DKIM/DMARC validation. So if I send an email from user1@domainA.com via the Postfix relay (using it as a smart ...

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