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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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177 views

Email server with no smtp connection

Ubuntu 18.04 on Google Compute Dovecot + postfix I figure I should be able to connect to a port other than 465/587, and since I can relay all email through google there should be no issue with this ...
4
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1answer
92 views

How to recover domain name from previous bad SPF record?

TL;DR: We had SPF too permissive (+all) and spammers used this to send tons of spam "from" our domain. We restricted that to ~all and added DMARC (not DKIM though), now other providers do not trust ...
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1answer
582 views

Postfix 2.6.6 with TLS - unable to receive emails from GMail (and a couple of other MTAs) but others are OK, why?

I've just had to look at a CentOS 6 server running Postfix 2.6.6 which was able to send emails to everyone, but could not receive them from GMail (and a few other MTAs) due to incoming TLS negotiation ...
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1answer
46 views

Sendmail relay alters recipient email?

Hello I am trying to set up sendmail on a Centos 7 server to relay mails from a local program to our main mail server. I have configured sendmail.mc with the following, mail.[domain].com is our SMTP ...
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43 views

setup Postfix gateway problems

I want to setup a PostFix mail server using gateway. I want two features. First, Mail send. MailClient ----> MyMailServer(10.0.0.2) ----> MyGateway(10.0.0.1) -----> Internet: Other MX Server ...
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0answers
92 views

Avoiding E-Mail spam filters (possibly based on originating computer?)

We recently started to send out a higher amount of E-Mails (invitations to a private event) to a select number of people. Now from some of those people using office365 for Mails, we were informed that ...
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32 views

I can't receive emails from my MT4 Platform

My MT4 platform sends emails with no issues (as per the Journal Log) so free (Yahoo, GoogleMail) accounts with no problem, but when I change the "To" email to my companies domain I can't receive ...
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1answer
35 views

Qmail SMTP receiver always delays by 66 seconds

I am currently struggling with a problem in my qmail setup, which seems to delay my smtp receiver everytime for 66 seconds. This is for most remote hosts fine, but some seem to reach their timeout and ...
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0answers
115 views

Postfix check_recipient_mx_access not working

My postfix install relays for quite a few different domains but I would like it to just shove all messages from one domain, destined for any Google MX's through the Google G-Suite relay service. In ...
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3answers
365 views

Dovecot SSL - IMAP works, SMTP fails

I'm setting up a small mail server using postfix+dovecot. When running oppenssl s_client -connect mail.myserver.com:993 (IMAP), the server's certificate is displayed and I'm able to get an email ...
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1answer
52 views

How mailchimp can sign email changing the domain and from header?

I've configured a SMPT server using postfix, dovecot, opendkim, openspf, openssl etc... I'm trying to figured out how mailchimp can send mails signed by their servers and deliver to recipients without ...
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1answer
254 views

Do I have to, and how do I setup bounce emails HELO command?

Our server has been listed several times on CBL (see this question) because it "attempted to send email without using the HELO/EHLO command". Grep'ing on HELO on Exim's logs, I found such suspicious (...
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0answers
79 views

Setup SMTP connection between mautic and iRedMail

I have set up my iRedMail on AWS EC2 small instance, now everything is working fine under port no 25, but I need to authenticate users to authenticate themselves. In mautic "to authenticate we need ...
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0answers
47 views

configure postfix to allow relaying for virtual mailboxes that are forward only

I have postifx configured as a simple mail forwarder. I have 4 virtual domains in /etc/postfix/virtual with about 10 virtual mailboxes on each which all forward to my business email address. Now, I ...
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1answer
61 views

Exim: Relay unknown recipients to another server

Question Can I force Exim to relay mails with unknown recipient to another host? Scenario I want to stage the Exim to Exchange migration in a way that would allow me to move individual accounts ...
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1answer
531 views

Postfix SMTP on port 587 errno connection refused only from localhost

If I connect from a website from the localhost (127.0.0.1) with port 587 and STARTTLS to my smtp-server on mail.example.tld, I get the the error "Connection refused, errno 111". Connections from a ...
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1answer
50 views

Domino Server Incoming Mail Mime Encoding

I recently installed FP10 to the Domino 9 server and made changes to http.cnf to AddType image/svg+xml .svg I am not running IHS. Incoming mail however now has encoded Subject: =?UTF-8?Q?...
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1answer
49 views

Echange 2013 internal server IP and name on message header

I have a server with Exchange 2013. Each message that is sent externally contains the IP and the internal server name. How can I hide this IP and internal name? Because some domains that reject the ...
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0answers
15 views

What are my technical options when it comes to scripting a message trace in an Ironport?

I need to automate message traces in a cluster of Ironports. What are my options? Based on my research I found A REST/XML style interface exists, but it only exposes monitoring endpoints for ...
0
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1answer
44 views

Server 2012 SMTP Server

I've stood up two SMTP servers using windows server 2012 r2, they send out email just fine but when an email does fail and we get a bounce back. Is that stored in a file somewhere so that I can use ...
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0answers
334 views

HAProxy - IMAP, SMTP, POP3 - Multiple Servers

Please accept my apologies if this is off topic or does not apply on a more broad scale (i've searched the internet and can't seem to find a solution anywhere). I'm not sure if this is even possible, ...
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0answers
84 views

Postfix: Script to difference hard vs soft bounces

I followed the steps mentioned in the forum - how to collect bounces for triggering a script upon a bounce receipt. Now, I would like to classify the bounce depending on the status. It would be ...
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1answer
268 views

Exchange 2010 “Microsoft Exchange Transport” hangs every time

Our small network (1 server, ~10 workstations) runs Exchange Server 2010 on Windows 2008 R2 Standard; it has worked fine for years, but recently we cannot send or receive mail, though no error is ...
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2answers
224 views

Single DNS and E-Mail server with multiple public IP addresses

On our site we have two internet providers, with public IPs on each link. We manage locally our DNS and SMTP server. We want to publish our DNS and SMTP server on both links, to get redundancy. My ...
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1answer
291 views

Postfix transport map always using catchall definition

Hoping one of the Postfix experts on here can help me debug an issue I am having with transport maps. I've gone through a the recommend list of questions to try and resolve my issue with no luck. ...
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2answers
68 views

Did Postfix deliver a mail via plain SMTP or STARTTLS?

Using smtp_tls_security_level or smtp_tls_policy_maps I can make Postfix deliver outgoing mail via STARTTLS. However, the log file doesn't seem to tell me whether the mail was sent using TLS. Jul 9 ...
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1answer
54 views

Caveats to SMTP Relay in email software or common practice?

One general question: I have a server on a shared host which IP constantly gets on blacklists of some mailservers (live.com, hotmail, ...). That means we can receive emails but cannot send emails to ...
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2answers
121 views

How does MS know which public IP addresses are dynamically assigned [duplicate]

I came across this article which says that Microsoft is blocking SMTP from dynamically allocated public IP addresses. https://support.microsoft.com/en-us/help/886692/microsoft-com-now-blocks-...
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0answers
212 views

SMTP working from localhost but not on shared hostning server

This is a weird scenario. I have two websites hosted on a Shared Multi-Domain Windows hosting server. I have setup e-mail on both websites and using an aspx script to send e-mails using the SMTP ...
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0answers
32 views

Windows 2012 R2 SMTP service issues

I have a server that for the past week or two has been having SMTP service issues with the service stopping and restarting infrequently. The service is set for automatic and the recovery options are ...
0
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1answer
180 views

How to configure Postfix SMTP to mail to another server from external client?

I have a server with Dovecot and Postfix installed. I have set up squirrelmail which works. I want to be able to send mail from a mail client on a computer other than the server (external) to gmail/...
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0answers
48 views

How can I define/rewrite Localhost in Postfix?

I am running Postfix on Centos 7 that routes sent emails to Office 365 SMTP relay. My configuration works fine for external recipients and for local recipients where I specify the FQDN address, like ...
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3answers
530 views

Can't connect to GoDaddy VPS SMTP server

I have an ASP.Net C# web application which sends out email notification. I configured it to use the SMTP server on our VPS to send the email. But if the application is not hosted on the VPS I get an ...
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0answers
33 views

Do some smtp servers refuse to SEND to a spam-blacklisted host?

Is it known that some mail admins or mail programs setup their server like this? Is this a small minority? I don't have any examples, but i'm just curious.
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1answer
766 views

Disable Postfix Open Relay

For the past few weeks someone has been using my server/postfix as a relay mail server. I tried everything that was posted in the hundred of other posts on this topics, but they are able to do it ...
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1answer
379 views

BDAT support for Postfix

Any idea whether Postfix supports BDAT command? I get this error: 550 5.6.11 SMTPSEND.BareLinefeedsAreIllegal; message contains bare linefeeds, which cannot be sent via DATA and receiving system ...
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0answers
369 views

Postfix with Gmail smtp-relay

I have been trying to connect my server running postfix to the smtp-relay.gmail.com. In the Logs I am still getting this result: Jun 25 18:48:39 server postfix/pickup[6378]: 096389FB60: uid=0 from=&...
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2answers
146 views

Centos7 / Postfix / Dovecot not receiving external email

I'm setting up my personal email server, after a while I was able to send emails out with correct DKIM/SPF settings. Right now i do not understand why I'm not able to receive email from external. ...
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0answers
248 views

Sending mail with ssmtp over IPv4

Apparently DigitalOcean blocks outbound SMTP on IPv6. I can confirm this with telnet as follows: ⟫ telnet smtp.gmail.com 465 Trying 2607:f8b0:400d:c07::6c... > Waits for about 2 minutes ...
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1answer
569 views

Postfix do not listen on SMTP Ports

i have a problem with my Postfix on Ubuntu 18.04. Problem seems to be Postfix do not listen on SMTP Ports 25, 465 or 587. UFW firewall is disabled. Telnet result to the machine on Ports 25,465 and ...
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1answer
121 views

Postfix doesn't send mails to own domain

I have a problem that my kopano / postfix on ubuntu 18.04 doesn’t send mails to my own domain. My domain is for example: example.com I try to send a mail from admin@example.com to admin2@example.com ...
0
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1answer
145 views

How can I enable SMTP receipt through firewalld on Linux?

I've leased a dedicated, lightly-managed CentOS7 box from a hosting company. The host came with firewalld installed and running and with its iptables preferences pre-imposed. I was not expecting ...
0
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1answer
118 views

Google Cloud Platform + Confluence Server + SMTP

I am trying to migrate my Confluence server to live in a vm hosted in Google Cloud Platform. So far so good, I got mostly everything working, except my mail setup. I read in google's documentation ...
0
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1answer
52 views

Close Port 587 - Ramifications?

Our recent PCI scan failed because "Plaintext authentication is allowed over unencrypted channel on SMTP." As such, our tech support suggested to close port 587. What are the effects of closing port ...
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0answers
52 views

Identifying suspicious outgoing SMTP connections (a.k.a. spam) after CBL listing

The IP of my email server has been listed on Spamhaus CBL, which states that the server "attempted to send email without using the HELO/EHLO command", "[which] is generally indicative of a broken ...
2
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1answer
65 views

Reject Exim authentication attempts based on username

Is it possible to set up Exim so that, based on the username passed along to it, it can reject an authentication attempt before it will try to do a password lookup for that username? I've done similar ...
0
votes
1answer
983 views

Office 365 Exchange, open relay by default?

We have an API that sends email. I was trying to set up Exchange O365 so that the API server could send email without authentication. I made some changes and tested and it worked, great! But then I ...
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3answers
410 views

Are CNAME “imap…” and “smtp…” subdomains needed?

I'm running my Postfix email server. I have only 1 A dns record for it: mail.my_domain.com I'm able to connect to it, receive and send email through it using only this url. Namely, I don't have "smtp.....
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0answers
35 views

Postfix Maildir saving file for each unique recipient

I have "home_mailbox = maildir/" and a catchall virtual_alias_map (/etc/postfix/virtual) /.*/ user All emails are landing in maildir/new/ successfully but for emails that have more than 1 ...
1
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1answer
706 views

Azure VM Outgoing SMTP to O365 Not working (Send-MailMessage : Unable to connect to the remote server)

Using Powershell from my local desktop, I am able to successfully send an outgoing email to our O365 email server: $mycredentials = Get-Credential Send-MailMessage -smtpServer company.mail....