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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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90 views

Combating a persistent spam list

We use Office 365 as our primary mail provider. We have an internal mail server that we use for relaying things like reports from our SSRS, scan to inbox for old scanners, etc. It is an IIS SMTP on ...
4
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0answers
218 views

How can I explicitly disable TLS when sending to one specific recipient?

I have a SendMail 8.14 server deployed in the middle of an SMTP workflow (Outbound mail looks like Exchange -> SendMail -> Appliance -> Internet) I have TLS configured for the first three hosts. ...
3
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0answers
235 views

With a period/dot in the name part of the address, Domino 9 SMTP won't accept incoming mail

Summary: Receiving mail to username@foo.com works, but user.name@foo.com doesn't. On an IBM Domino 9.0.1, a proper Global Domain document exists for the domain foo.com One user has two email ...
3
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0answers
364 views

Don't send outgoing mail via Spamassassin

My e-mail server is running Postfix 2.11.3 on Debian 8.7 (Jessie) with Spamassassin 3.4.0. I realized that my outgoing e-mails are also being checked for spam, which not only seems to be unnecessary ...
3
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0answers
111 views

Postfix doesn't send email, only receive

I recently install on my Debian Server the PostFix + Dovecot + Mysql, everything works fine, but I cant send email, I receive the error on the log NOQUEUE: reject: RCPT from unknown[##.4.##.41]: 454 ...
3
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0answers
55 views

vCenter email notification has a semicolon/SMTP does not recognize it as a valid email address

Messages from vCenter has this header info: Received: (from root@localhost) by (8.14.3/8.14.3/Submit) id u92F2su5032029; Sun, 2 Oct 2016 15:02:54 GMT Date: Sun, 2 Oct 2016 15:02:54 GMT ...
3
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0answers
88 views

Postfix STARTTLS works in LAN but not externally

if I connect in LAN on port 25 to my mail server, it offers STARTTLS telnet mailserver.com 25 Trying 192.168.0.x... Connected to mailserver.com Escape character is '^]'. 220 mailserver.com ESMTP ...
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2k views

hMail Server SSL Certificate Verify Issue | TLS/SSL handshake failed

I will tell you my situation step by step and ask me any necessary questions and help me to fix hmail certificate issue. First of all : 1- i am using a windows server 2008 - r2 2- latest hmail ...
3
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0answers
2k views

Outlook.com rejects: 550 SC-001 (BAY004-MC5F13)

I am operating a cluster of 3 dedicated machines for a webapp, each of those uses sendmail as MTA. Hostnames are node1.domain.com node2.domain.com node3.domain.com Unfortunatelly outlook.com rejects ...
3
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0answers
1k views

nullmailer swaps sender and recipient

I want to send emails from my server through external mail server. So I installed nullmailer as one of simpliest MTA in Debian 7 x32. My /etc/nullmailer/remotes: smtp.example.com smtp --user=sender@...
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0answers
386 views

How to identify the user/computer that is relaying spam through a mail server?

For the past couple of days, at certain intervals, a huge load of email is dumped on my Exchange 2003 server and relayed out until it gets blacklisted everywhere. Nothing like this happened for many ...
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0answers
62 views

Why is Exchange 2010 SMTP not rejecting external messages to internal-only groups?

TL;DR: How do I make sure that the SMTP server doesn't accept external messages for distribution groups that are set to require authentication? I have an Exchange 2010 server that has multiple ...
2
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0answers
47 views

Connecting to a external exchange server via linux/php?

We have an SMTP relay available that we are using on windows servers. [mail function] ; For Win32 only. ; http://php.net/smtp SMTP = email.relay.url ; http://php.net/smtp-port smtp_port = 25 ...
2
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0answers
78 views

Prevent postfix from trying secondary MX after soft bounce from Google MX servers

My local SMTP relay is finding it increasingly difficult to deliver mail to my G-Suite groups and users. The volume is not very high, but Google enforces rather low limits on incoming e-mail from ...
2
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0answers
164 views

postfix connection timed out inbound port 25

i have a "small" problem with incoming email from certain customers. in 2 occasions i got xxx.xxx.xxx.xxx:25 Connection Timed Out. however port 25 is open, also in ufw allowed. i can even telnet and ...
2
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0answers
214 views

How can I customize before-queue milter replies in Postfix?

Currently I use postfix with spamass-milter and clamav-milter as before-queue milters, which both work very well. I reject hundreds of messages a day on my small personal mail server on the basis of a ...
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0answers
1k views

How to detect SMTP AUTH attempts in Fail2Ban?

I have a Fail2Ban jail that monitors failed SASL authentications to my Postfix SMTP server. When this occurs, /var/log/mail.log contains these three lines: postfix/smtpd[32591]: connect from unknown[...
2
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0answers
696 views

Does Google require TLS on port 587? Exchange 2010 SMTP has mail sent to GMAIL backed up in queue

Exchange 2010 SMTP has mail backed up in queue. Any email sent to Gmail sits in the queue while any email sent to another personal domain which has email filtering enabled errors, "asp.reflexion.net ...
2
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0answers
565 views

Getting “5.7.1 Unable to Relay” intermittently on mails sent to Exchange 2013

I have a helpdesk system that sends mails through the local exchange server. Until a few days ago, I never had issues with it. For the last week we have started getting complaints about missing ...
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0answers
2k views

When does Postfix not perform lookups in virtual_alias_maps?

I'm having a real pickle of a problem: I have a Postfix 2.6.6 / CentOS 6 server that's set up to forward mail from specific aliases to specific destinations. This is done through a mysql ...
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0answers
908 views

Stop IIS SMTP Server from sending “Delivery Status Notification (Failure)”

I have set the BadMail directory and the 'Send copy of Non-Delivery Report to' fiels is empty but, somehow I am still receiving the failure messages. Is the a way to stop the failure messages?. I am ...
2
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0answers
35 views

I need to set-up the blocked machine to relay to the unblocked machine using a different port

I have two Windows Server 2003 machines sitting in a network. Server B has port 25 open and can relay emails to the local network's smtp server. Server A does not have port 25 open. How can I set it ...
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0answers
440 views

Forcing IIS virtual smtp server to verify outgoing TLS certificate

I am in a situation where a web application is using the IIS virtual SMTP server to send out email. The IIS virtual SMTP server is then configured to send all mail out through a smarthost, over TLS ...
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0answers
285 views

How can I change the default email address format type for replies on blackberry?

Exchange 2007 BES 5.0.x Hello all, I'm trying to help a colleague with a technical issue. I apologize in advance for not having all of the information. I'm looking for some advice on where to ...
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0answers
23 views

Can't find the IP address of a Saslauthd login attempt

I need help locating the origin IP from this error messages/ login attempts: From the 'sasl auth daemon' via Logwatch: pam_unix(smtp:auth): check pass; user unknown pam_unix(smtp:auth): ...
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0answers
55 views

IIS 7 SMTP not relaying one specific domain

We have an old 2008R2 Server with IIS running a SMTP process that is set to relay internal emails to an exchange server (external go out). We have 12 domains setup and all work well apart from one ...
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0answers
43 views

Configure postfix to send emails per domain from each virtual server

In my setup I have installed virtualmin for virtual servers. I have following virtual servers with their own dedicated ip address. Postfix is configured as per this method to use dedicated ip for each ...
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0answers
69 views

Server 2012 R2 SMTP service not sending mail to non TLS servers

We have SMTP virtual server on server 2012 R2 server. I have configured it to use TLS connection. We do have real sertificate etc. Everything works fine except mail that is going to mail server which ...
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0answers
76 views

Where does sendmail get its user authentication information?

I set up a new remote CentOS email server using sendmail and dovecot. I am able to receive mail into mailboxes but can not use SMTP to send. Trying to login by hand using # telnet mail.steelydev....
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0answers
120 views

Postfix transport based on source IP address (with or without relayhost)

We have Postfix relay server running on centOS 7.4. Restricted source IP address by mynetworks cidr mynetworks = cidr:/etc/postfix/allowlist.cidr Now, I like to configure, some of the source ip ...
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0answers
364 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
44 views

IIS6 SMTP server sending blank 'From' addresses within bounce messages

I have a basic SMTP setup configured using IIS6 to send out site emails on my server. I've been scanning through the badmail directory and have noticed the following type of notification occur. It ...
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0answers
470 views

SMTP Relay suddenly stopped working

Our SMTP relay has been stopped, we are using office 365 email account for this purpose. I have searched a lot on the net but unable to find the solution. Our environment is based on below Server (...
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0answers
345 views

SMTP connection lost after final dot on exim4 Debian

I have an SV3C camera (very cheap MIC) that has a poor SMTP implementation I'm using exim4 to send mail from it. Although the connection test says succeeded my exim4 log shows: 2017-10-21 11:17:08 ...
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0answers
58 views

Set up client ceritficate file path for external SMTP server in GitLab

Is it possible to set up GitLab to use external SMTP server which configured to accept connection only with client SSL certificate? I have no idea which parameter can I use in GitLab smtp ...
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0answers
556 views

Postfix: Temporary internal error / Dovecot: Initialization failed

Today I wanted to make a mail server, but it did not work. Can you help me ? I followed this tutorial: https://www.linode.com/docs/email/email-with-postfix-dovecot-and-mysql Errors obtained: Sep 19 ...
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0answers
53 views

Postfix 3.2.0 - Sending to all MX records

Firstly, apologies if I haven't included all of the relevant information in this initial post. Please let me know if I have missed anything. I am currently running Postfix 3.2.0 and have a problem ...
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0answers
1k views

Exim not Listening on port 465 or 587 for TLS connection

I am configuring Exim on a Ubuntu server to send and receive mails via TLS. Followed many guides which shows on how to configure Exim with TLS but still my Exim doesn't listen on 465 or 587 Exim ...
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0answers
447 views

Configure fail2ban notifications using sendmail (Unknown user)

I am trying to make fail2ban send me notifications when IP is banned. But I have troubles with configuring MTA. It is a really tricky task. I have tried multiple MTAs (mailx,exim ...) but I've failed ...
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0answers
544 views

SSL Handshake failed (IceWarp mail server)

We have an SMTP client custom software that has worked perfectly until recently with our SMTP server. We changed nothing in the settings both of the client and the server, but the client software ...
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0answers
201 views

SharePoint 2013 doesn't send emails

My SharePoint 2013 has stopped sending emails suddenly. I have checked my SMTP settings and outgoing email from central admin and have tried to use PowerShell to test it via this command: [Microsoft....
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0answers
767 views

Most received mails are marked as spam

I use Google Mail for all my personal mails. I use a custom mail address which is configured to forward all mails to my Google Mail account. When sending mails I use the feature to use another smtp ...
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0answers
55 views

Postfix routes mail it could not deliver to the relayhost

When a message can't be delivered locally for some reason, Postfix uses the relayhost to send the message there, which is IMO pretty pointless. How can I prevent that and either generate an error mail ...
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0answers
1k views

Exim and PHPMailer: can't accept authentication when host is localhost

My issue: Using PHPMailer I can't send authenticated SMTP emails when using the localhost Host. I can't see why this is so. I realise the core root of the problem here is almost certainly a setting ...
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0answers
496 views

I have to input HELO/EHLO commands twice before it registers on receiving server while testing SMTP

We have an Exchange Server (2010) on site that sends our mail to the world using MX(DNS) records. When I look at the queue, several domains have 421 4.4.2 Connection dropped due to ConnectionReset. I'...
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0answers
2k views

354 End data with <CR><LF>.<CR><LF>, mail not sent

I know, there is already an answer to this smtp-status, but sorry: i don't get it. A Customer of mine sends a big amount of mails and some can't be send cause of: This is the mail system at host ...
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0answers
198 views

How can I route messages from Intermedia Exchange to Office 365 if they share the same domain?

I would like to route messages from Intermedia Exchange to Office 365 where both environments share the same domain. (example.com) To complicate this situation, the domain example.com is also hosted ...
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0answers
36 views

How to cope with only one SMTP socket open simultaneously on VPS?

I own a VPS used for hosting about 30 domains. On each domain I have several email accounts. In total more than 150 accounts. In the last couple of weeks, I noticed that sometimes (several times a day,...
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0answers
160 views

Postfix. Sending some messages using external smtp server and some messages “directly”. Issue with sender_dependent_relayhost_maps

I'm configuring a new web server and i need to make emails from my PHP scripts to be sent. Most messages should be sent using mandrill SMTP and some "directly" from my server to email services. I ...
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0answers
63 views

IIS 6 Sending rules

I need to send all emails out as normal with the condition of gmail.com & gmail.co.uk emails. Which need to go via the google smtp relay service. Is this possible to setup on IIS 6? Basically 2 ...