42
votes
sendmail can not deliver to gmail - IPv6 sending guidelines regarding PTR records not met
Check the current protocols:
postconf inet_protocols
net_protocols = all
Edit cf File if it returns all
grep 'inet_protocols' /etc/postfix/main.cf
inet_protocols = ipv4
Restart
service postfix ...
20
votes
Accepted
Postfix - gmail encryption
You are missing the smtp_tls_security_level directive.
smtp_tls_security_level = may
This will set it to opportunistic TLS, using encrypted connections if the server supports it, but allowing ...
14
votes
Accepted
Why don't my domain's messages to a google group get their headers rewritten so DMARC can pass?
I did finally get this response from Google. I was glad to find someone who understood the issue, but unfortunately it looks like Google is sticking with their incorrect treatment of the DMARC ...
14
votes
How can the `to:` and `delivered-to:` fields in an email i received be different?
Just like snail mail letters, SMTP email has two different sets of address information: the envelope headers (like the addresses printed on the outside of an envelope) which are used by the SMTP ...
13
votes
Accepted
Postfix - Untrusted TLS connection
Is there an easy way to gain a Trusted TLS connection instead of untrusted, do I need to buy something or this free certificate should work?
This is not about your certificate, so you don't need to ...
12
votes
Why doesn't "dig gmail.com mx" return the domain "smtp.gmail.com"?
How about the smtp.gmail.com, why isn't it included?
Because smtp.gmail.com doesn't receive email for the gmail.com domain. You asked for the MX record for gmail.com. The answer you got was exactly ...
11
votes
Accepted
Gmail flagging Dovecot email as insecure
I solved this by adding both these lines to Postfix's main.cf:
smtp_tls_security_level = may
smtpd_tls_security_level = may
(I had only set smtpd_tls_security_level because of a misleading article ...
10
votes
Accepted
Why does DMARC operate on the From-address, and not the envelope sender (Return-Path)?
Think of SPF and DKIM as ways to validate the mail path, and think of DMARC as an extension that also validates the message sender. Think of this as delivering a FedEx letter. It's easy to validate ...
10
votes
Accepted
Mail from Teams forwarded to Gmail marked as spam due to DMARC failure
I would assume its Microsofts fault for breaking their signature. The headers clearly say that the signature was good before forwarding, and then broken on receipt by Google. Checking the signed ...
9
votes
Why doesn't "dig gmail.com mx" return the domain "smtp.gmail.com"?
As joeqwerty rightly points out, it doesn't show smtp.google.com because a MX record indicates where mail servers should send messages destined for that domain. This is not the same as the servers ...
9
votes
Why doesn't "dig gmail.com mx" return the domain "smtp.gmail.com"?
My initial goal is find all smtp servers of an email provider.
You can't.
8
votes
Amazon SES instead of Gmail for company email
SES is not designed for this - SES is primarily for automated sending email, with the facility to receive email and send it to automated systems via Lambda, SNS, or stored on S3. Sending would ...
7
votes
Gmail flagging Dovecot email as insecure
Your email is sent unencrypted.
If you just want to try your best add the following to your main.cf
smtp_tls_security_level = may
To enforce TLS encryption for email sent to google add this to your ...
7
votes
When DKIM is installed, will I still be able to send email for my domain from gmail?
DomainKeys Identified Mail (DKIM) is for ensuring that mail content hasn't tampered during transmission. Unlike Sender Policy Framework (SPF) it's not trying to validate the source of the message as ...
6
votes
How to check if a mail server is flagged as SPAM by GMail?
Go to http://postmaster.google.com/ and sign up there, this is recommended by Google https://support.google.com/mail/answer/188131 for blocked emails.
Google provides you there with your individual ...
6
votes
How to send a mail with a URL with swaks?
The email without the mime headers would come across as plain text. The mime headers make the message body gets seen as HTML.
swaks --body '<a href="https://en.wikipedia.org/wiki/Main_Page">...
6
votes
postfix: Cannot assign requested address
The delivery attempt on the second log excerpt tries to use IPv6 and after failing, falls back to IPv4 and delivers the message successfully. You can either fix your IPv6 host configuration if you ...
6
votes
Is ed25519 well supported for the DKIM validation?
As of 2022-01, not a single big mail provider regularly verifies ed25519 signatures, though the reported result will not be consistent, I have seen in DMARC reports (along with pass for other ...
6
votes
Accepted
Gmail does not accept mail from a new VPS server with PTR setup
Your PTR record for IPv6 is setup correctly (and strictly speaking it seems to be no longer required by Gmail).
Saying that one hint is in the message Gmail sends to you:
or the corresponding forward ...
5
votes
monit send email does not work
You can use a remote mail server. Here are my sample configs which worked. It sends alerts to my gmail through a remote smtp server. I think you still use Gmail as an smtp relay as well.
#configure ...
5
votes
Why does DMARC operate on the From-address, and not the envelope sender (Return-Path)?
There are two "why" questions:
Why does a receiving mail server perform the check in this manner
because that's what section 3.1 of RFC 7489 says to do
Why was DMARC designed that way?
...
5
votes
Gmail flagging Dovecot email as insecure
Consider the client/server relationship with regards to SMTP and the settings make sense:
2.1. Basic Structure
The SMTP design can be pictured as:
+----------+ +-------...
5
votes
Postfix can send mails to all domains except gmail
You seem to be using SMTP port 25 for both incoming and outgoing mail. Because you have
smtp inet n - - - - smtpd -o content_filter=spamassassin
spamassassin unix - n n - ...
5
votes
Accepted
Postfix smtp relay quota and configuration for Google Suite (Gmail)
I finally discovered that G-Suite has a documentation article for this exact question.
Depending on your requirements, the available options are:
G Suite SMTP relay service — Send mail from your ...
5
votes
Somebody bought my old domain and I can't access my old mail
"I don't have access anymore to the email account that was used to sign up" is not a rare occurrence.
People commonly use their work email and will lose access to that once their ...
5
votes
Two mail providers for the same domain
you cant have two different providers for the same exact domain, but you can have a different subdomain for some emails.
you could have the important email at google , for [email protected] , ...
4
votes
Cannot send email from EC2 instance on port 587
For send an email from AWS EC2 using Gmail SMTP service please follow below steps.
Edit security group of your EC2 Instance.
Edit inbound rules of the security group.
Add 587 port in inbound rules. ...
4
votes
Remove "via" from emails sent to Gmail from Amazon SES
If your 'from' description contains certain special characters it can fail even with everything set up correctly.
eg. having a registered trademark in my 'from' screwed everything up
var toAddress = ...
4
votes
Can you configure MS Exchange to support the gmail "+keyword" trick?
This feature is now available on Office 365 Exchange!
Exchange admins will have to enable this manually on their server. This can be done through Powershell using the following command:
Set-...
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