Questions tagged [smtp]
SMTP is the Simple Mail Transfer Protocol, the most recent standard of which is defined in RFC 5321. It's the Internet standard for sending and receiving email.
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What could be causing PowerMTA not to forward emails over port 465 SSL...?
We have a PowerMTA server that receives incoming e-mail. and forward it to external SMTP server that's not running PowerMTA i tried to do it using port 587 and port 25 both working fine and emails ...
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SMTP Relay - Keep sender SPF valid
We use a email setup (incoming mails) in the following order:
Internet -> on premises mailserver (=> attachment filter, antivirus, spam filter) -> forward to Microsoft 365 Exchange Online ...
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IIS SMTP relay stops making outbound/forwarding connections
We have IIS 6 setup with SMTP relay which suddenly stopped sending out e-mails. I can see the mails are stuck in the Queue folder and on the logs, it was no longer making Outboundconnectioncommand/...
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Postfix - Relay - authentificatin in Mysql
I tryed to manage with a postfix server, my goal is that :
When 1 special user (test@example.com) try to send mail, it will use routing (using a relay server is OK) but I don't understand how to send ...
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Redirect OR warn (during initial negotiation) SMTP submitters to use TLS on port 587 - leave 25 explicitly blocked by firewall for better security [closed]
I've managed to find a lot of closely related information, but not an answer truly addressing my question.
I am expanding on my homelab server, and have decided to use a small publicly hosted server ...
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Best Practice - SMTP Time Out
Good Day,
The question is quite straight forward. What should be a best practice to time out a SMTP connection on the RECEIVING side?
Background: We are currently having an issue with a sender that ...
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Postfix to gmail relay - preserving the sender's address
Relayed emails come 'from' me@gmail.com, not sender@theirdomain.com, so I cannot reply.
I have several domains and am using Postfix to relay emails sent to me@mydomains.com on to me@gmail.com as ...
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how to switch from outgoing port 25 to 587 in postfix
I would like to send a mail to a gmail address:
echo "This is the body of the email" | mail -s "This is the subject line" user@gmail.com
That is what I see in the logs
connect to ...
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SASL Authentication - Why is it taking so long to login to the authentication server?
I can't describe it properly, but I have a Thunderbird mail client, I use it to receive and send mail through a user I created and an available domain. I use IMAP and POP3 services there, I also have ...
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iptables - port 25 not getting traffic even though default policy is ACCEPT and all rules are flushed
I am having a problem that's driving me up the wall. I have a server, where after several attempts at various iptable rules, I have flushed iptable rules and set default policy to accept.
The output ...
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Exim allow outgoing for specific domains
I am using Exim as MTA. I want if an email is sent out from my server, then the sender domain must be in the list "+local_domains", else it should be through the message "Not Allowed&...
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Dell IDrac8 SMTP setup diagnosis - RAC0225
I tried to setup the mail warnings on an IDrac8, it's not my first time, that's why I am wondering what I am doing wrong.
on this server it won't send mails with following error
"RAC0225 sending ...
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Postfix/Dovecot - Initial Config - Test Email Results - 554 5.7.1 Client host rejected: Access denied
I sent an email successfully. Can't say the same for receiving. When I attempt to, I get an email saying that the message was blocked with the following diagnostic code:
Diagnostic-Code: smtp; 554 5.7....
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Configuring Google Workspace (Gmail) to trust a Mail Relay via ARC?
I am building a system which modifies incoming emails body on the fly (for example, it deletes attachements with viruses). Of course, I break the DKIM signature when there is one. Is it possible to ...
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Using an existing Postfix + Dovecot server, how do I relay mail not intended for my configured domain?
I have a Postfix + Dovecot server that is receiving public mail and allowing folks to view their mailboxes using IMAP just fine for a particular domain (let's call the domain mail.acme.com). But, I ...
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opendkim-testkey: key not secure (file permissions are good and TrustAnchorFile config setting is set)
If I run sudo opendkim-testkey -d mydomain.com -s selector -vvv, I get
opendkim-testkey: using default configfile /etc/opendkim.conf
opendkim-testkey: checking key 'selector._domainkey.mydomain.com'
...
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Exchange Server 2019 can't send email on port 25
I have setup a windows server 2022 with Exchange 2019 and am unable to send out email because outgoing port 25 is blocked.
Vultr.com says they have removed the default SMTP block from my barebones ...
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Why exim does not use TLS when sends email to remote SMTP?
Here what exim does when sends emails to gmail and other SMTP severs
Received: from ns01.virtex.kz (ns1.virtex.kz. [185.141.164.16])
by mx.google.com with ESMTP id i11-...
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What exactly is Return-Path and who sets it?
This article (https://www.sparkpost.com/resources/email-explained/return-path-explained/) explains "Return-Path" as follows:
When an email doesn’t make it to its intended destination, the ...
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Gmail not detecting PTR record from vultr server
I have an SMTP server running on a vultr VM. I've set up the rDNS to point to my mail domain name mail.idimitrov.dev. The DNS setup points to that machine on ipv4 and ipv6 for mail.idimitrov.dev and ...
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Postfix white listing a badly configured server not working: Helo command rejected: Host not found;
My mail server configuration is rather strict and some times incoming mails from legit servers get rejected because the remote end has a configuration problem, a common one is the HELO hostname.
I ...
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Configuring postfix to use SendGrid SMTP relay with fixed FROM address but need to append REPLY-TO of original sender
I have been trying to resolve for a couple of months using multiple different configurations.
The local delivery to a Dovecot mailbox (originalto@domain.org) keeps the original sender (sender@gmail....
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postfix huge qmgr pickup and cleanup and low smtp process
i have postfix version 3 i am using it as MTA relay it receives huge amount mails from users and deliver small ammount trough smtp , in one minute there is 500 mails in queue as active and 1 smtp ...
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AD lockout email alert script working intermittently
So we've been using this PS script for a while and was working fine until we migrated the domain controllers. The new domain controllers are running core Microsoft Windows Server 2019 Datacenter. We ...
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Slow SMTP responses with Exchange 2013 (Not network infra related)
(I know 2013 is shortly out of support, and it will be replaced, but in the interim, I'm experiencing an issue I would like to fix.)
I will use telnet over port 25 as my example, but normal traffic ...
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Nginx mail proxy: tls between the proxy and the server?
When using the Nginx Mail Proxy feature to realize an SMTP proxy, there are several options available to configure (start)tls between the client and the proxy.
However, it appears between the proxy ...
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Haproxy will not load balance smtp
I have been struggling with Haproxy for a long time now to configure smtp load balancing. Whatever I do, the server responds with a black screen and no possibility to try out smtp commands to test. ...
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Mailgun Suppression List functionality
Running a mailman list on Redhat using Postfix. Trying to understand a couple of closely related concepts about Mailgun's Suppression List or Bounce List.
Is it "permanent", in the sense ...
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mx record with IPv6 AAAA host
I need to setup a mail server or mx record with a IPv6 address
I have written a AAAA record which is working fine (pings, ports) here
I have setup hmailserver and checked all ports(587, 143) with ...
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Emails are not being received from website contact form, due to server configuration?
Hello,
I have an e-mail address, let's say info@domain.com that is hosted on Hosted Exchange (cloudorb). Webhosting company A is managing the DNS records of that e-mail address. The website, let's ...
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How to improve sender score for personal mail server
Background:
I have an own domain and an own mail server that sends out the mail for this domain. The users are only my family so there are less than 10 users with probably 20 mails sent per day.
...
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Email proxy architecture
I'm trying to figure out how email proxies generally work. I want to present the way I see the architecture, would be glad if anyone could explain which of my assumptions is flawed and what am I ...
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After installing Tailscale and sending email, my IP was listed on eXploits Blocklist (XBL)
I installed Tailscale on most machines in my office yesterday. Shortly after, outgoing emails started being bounced back with this description:
host XXXX.smtp.a.cloudfilter.net [IP]
SMTP error from ...
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Root domain in SPF record instead of full hostname
Can i use root domain like google.com instead of _spf.google.com in SPF record?.
My SPF record
v=spf1 include:_spf.mx.cloudflare.net include:_spf.google.com include:mxsmtp.sendpulse.com +a +mx ~all
...
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231
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Whitelisting Gmail SMTP in CSF
In my csf.deny, I have 0.0.0.0/0 blocked to prevent requests being sent to the raw server IP. This creates issues with sending e-mails. I utilize Google SMTP to send e-mail. I can't seem to figure out ...
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Generate DKIM for Gmail Free Account
I am using Gmail SMTP with wordpress to send mail with my custom domain (user@example.com). Emails are successfully sent but always land in spam folder in every webmail provider (Eg, Gmail, Rediffmail,...
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Postfix: different smarthosts per server port
I need to install Postfix and let it listen on two different ports: 1025 and 1026:
/etc/postfix/master.cf:
1025 inet n - y - - smtpd
1026 inet n - ...
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Client is sending SMTP emails but they are not recorded in the "Sent" folder in webclients
I have been using instantly.ai to send emails. I connected IONOS.ca and JustHost.com mailboxes to instantly and it works fine (warmup, receiving and sending [yes other emails receive the emails sent, ...
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Postfix "Client host rejected: Access denied" how to diagnose the precise reason?
I see this question asked over and over on serverfault, and each time it seems to accompanied by a copy of the configs and result sin a successful or not diagnosis by wonderfully helpful readers.
I ...
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Possible to host own SMTP server without port 25 open
I have a VPS on Digitalocean and Hetzner, but both block port 25, so I cannot host my own SMTP server here. However port 587 is open, so my question is: Is it possible to host your own standalone SMTP ...
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apply header check for specific machine (IP)
I'm new to postfix (and also linux world)
My goal is to add a custom subject for a different machine (IP) who contacts my relay.
I use header_check to replace the subject of mails and it works but for ...
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Inetmgr6.exe missing on Windows server 2022, SMTP relay still working
4 months ago, I have in-place upgraded a 2K8R2 server to 2K22.
It had the SMTP relay function, and this feature is still working on Server 2022. (I did the export-import function to get the settings ...
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exim4: how to add an address as BCC to all the outgoing emails?
I'm working on an Ubuntu 20.04 web server where exim4 is used to send emails from the PHP application running on it.
Due to diagnostic and archival needs, I need to configure exim4 to automatically ...
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POSTFIX allow other domain to send emails from my SMTP server
I want to allow another domain to use an account on my SMTP server noreply@example.com, and allow it to send emails from my MX records through SMTP.
Do I need to make my server relay emails, or just ...
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I setup DMARC p=reject on server but now I can't send via gmail to gmail (using server email From address)
Did I shoot myself in the foot ?
I mainly use gmail to send and receive emails. Support etc. My default 'send email as' profile is not the gmail address itself but an address on my server (also the ...
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Receiving Mail in Google Cloud (SMTP Relay-Mailjet) on EXIM
I am using DirectAdmin on my server. I have configured EXIM. I can send e-mails, but I have not been able to receive e-mails. For example, when I try to send e-mail via example@gmail.com, I either get ...
google-cloud-platform
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Postfix - limit SMTP user to be able to send to certain domains only
What I'm basically trying to do is to restrict some SMTP email accounts to deliver to certain domains only. For example I have user jay@example.com who should eventually only send emails to addresses ...
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postfix logs showing ??? as command from client
I am running an Ubuntu 18.04.6 LTS server with the postfix 3.1.0-3ubuntu0.4 package.
Both the Apple Mail client and the Postbox client experience a weird delay when first sending an email to the smtp ...
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why gmail smtp reply message size limit is different [closed]
According to google documentations with following link https://support.google.com/a/answer/1366776?hl=en , message size limitation for inbound emails is 50 MB but as i was testing gmail smtp server ...
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Relay Host change
I have example.com configured as using relay mailjet.com and also the emails associated with that like somebody@example.com.....I would like this somebody@example.com to use another relay which is ...
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