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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Can't send email on Windows Server 2008 with Mailenable

I've got a VPS running on Windows Server 2008 and I'm using Mailenable as an Email Server for POP3 and SMTP. I've had the VPS since January 2015, its my first time configuring a server by myself, but ...
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2answers
18 views

Postfix SMTP Relay Configuration Error

For the last day I was searching for solutions for this problem: My postfix(+dovecot) configuration is fully able to receive e-mails and to serve them via IMAP but it fails at accepting them via SMTP ...
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1answer
11 views

How to reinject scanned mail into the queue using sendmail

I would like to pass incoming mail using virtual_transport to a transport spamassassin (main.cf: virtual_transport=spamassassin) and then reinject the scanned mail into postfix using sendmail. The ...
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0answers
13 views

free smtp server on laptop, mail rely [on hold]

How to set up mail relying from laptop with GNU/Linux to outside world? I want to use different mail clients (mutt, thunderbird, mail command,…). Notebook is connected to different networks, so ...
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2answers
30 views

How do I setup a server to send emails after starting (i.e. not meaning as an email server)?

Windows Server 2012 R2 w/ GUI, UPS system I am setting up my first server. It is a Hyper-V host that will host multiple VM servers. The system is on a UPS. When the UPS detects an AC power ...
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0answers
37 views

Differences between Exchange's “default” SMTP certificate and others enabled for SMTP?

I know that: You can enable the SMTP service for multiple certificates in Exchange The last certificate enabled for SMTP becomes the "default SMTP certificate" My question: What are the ...
3
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1answer
12 views

Routing SMTP Connections to Different IP Sets with IPTables

I'm trying to set up two different IPs for SMTP that each get routed to two different sets of IPs, with no IPs shared between the two sets. I'm trying this, but it mixes the two sets of IPs so that ...
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1answer
31 views

Alternative solution when Port 25 is blocked [closed]

I'm running a web server on my VPS (debian & webmin) for hosting my wordpress website along with others too, i've also tried to setup a mail server (postfix+dovecot) but unfortunately my VPS host ...
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1answer
32 views

Wildcard MX record support?

Let's say I want to start a service where customers get their own subdomain on my domain for email addresses only. I have an A record for mydomain.com and a CNAME for www.mydomain.com If I add a ...
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1answer
11 views

Exchange 2013 return message for old addresses

In my company there are two kind of smtp address in exchange 2013 recipients: j.deere@mycompany.com (old) john.deere@mycompany.com (new) Now I would like to remove all old addresses (j.deere) but I ...
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1answer
23 views

My server mail going junk in hotmail and yahoo [duplicate]

All my server mails going to spam in hotmail and yahoo. Here is my full mail source. Can any one please help me to sort out this issue ? ...
3
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1answer
34 views

How can one configure exim still to reject invalid recipients after an earlier ACL returned “discard”?

For the reasons set out in my earlier question Originating (non-critical) emails from a "less-trusted" host, it unfortunately seems that we must run an SMTP server for the sole purpose of accepting ...
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1answer
43 views

How do I set up an MTA to prevent spam relay? [closed]

I'm trying to secure my MTA against relaying spam, and am trying to understand what's involved. For example: Say I send an email using an Yahoo account to a Gmail account. When Yahoo is relaying ...
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0answers
15 views

NDR on all mail send

We have an old SBS 2003 running Exhange 2003. Since Tuesday some people start complaining that mail that they send out bounces back. On Tuesday afternoon almost everybody was affected. On a test that ...
5
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3answers
75 views

What to do if one doesn't want to receive email bounces?

Background—the standards RFC 5321 §4.5.5 states: All other types of messages (i.e., any message which is not required by a Standards-Track RFC to have a null reverse-path) SHOULD be sent with ...
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2answers
27 views

Smtp sending via Exchange some mails do not complete but still send - why?

I have an application that sends smtp email via a local Exchange server at a customer. All the email sends ok (it gets to the recipient) but some email gets sent multiple times because my application ...
5
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1answer
65 views

postfix dovecot disable lmtp

I have 3 servers. 1 MX server with postfix and 2 dovecot servers. MX server receive emails and then serve them through LMTP to specific dovecot server. All mailboxes from same domain are on same ...
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0answers
27 views

Postfix relay smtp to 2 relayhosts for same domain [duplicate]

have a setup in which Postfix relays mail for a specific domain to another mail server (Exchange) via the usual transport file: # /etc/postfix/main.cf transport_maps = hash:/etc/postfix/transport # ...
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1answer
39 views

Configuring Reverse DNS on Windows Server 2008, can't send email

I run a VPS on a Windows Server 2008 machine, and since I got it in January 2015 everything has been running fine, the server has IIS, DNS, and uses Mailenable for email exchange. I've been running ...
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0answers
9 views

Show blocked SMTP connections in Exchange 2010

Currently, I have an anonymous receive connector set up on my Exchange 2010 system that allows from an entire subnet. I'm looking to change this to only allow from specific IPs, but need to know when ...
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1answer
40 views

iptables KVM prerouting SMTP

I have a host machine that has to manage traffic on port 25 and route to port 25 on the KVM machine for postfix deamon like this scheme: WAN --> (25) HOST_MACHINE --> (25) ...
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0answers
52 views

ubuntu firewall blocking smtp tasks, port 465 is open

I have been trying to get my Wordpress site able to send emails, and it DOES WORK but only work if I turn off the firewall. I am using UFW. However, I do have port 465 (connecting to gmail) open while ...
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0answers
29 views

OpenVZ - SMTP - telnet - Connection timed out

I have problem with SMTP in my OpenVZ container. I've created OpenVZ container by Proxmox on dedicated server in OVH. This container will be as mail server. So I create on "mother-server" rules to ...
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2answers
138 views

Can't communicate with SMTP server from particular machine

Here is the situation: When I run the following on my local machine, the mail server responds: $ telnet mail.server.com 2525 Trying <mail.server.com IP>... Connected to mail.server.com. ...
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1answer
35 views

How would get an email server reputation via cli or script?

I am trying to monitor email server reputation via cli or script i.e. https://www.senderbase.org/ I found a way supposedly to do it via dig, but the output appears to be very incorrect. It indicates ...
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0answers
46 views

Major Mail Issue - SMTP Local Server Not Working

My database (MySQL), web server (IIS 8 ) AND SMTP server (IIS 6) are all on the same dedicated server (Windows Server 2012) that I'm honestly renting for a bit of system admin practice. I followed a ...
2
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1answer
37 views

Authentication error connecting to a mail server via openssl in the terminal

I've set up an email server using Postfix and Dovecot and I'm able to send and receive mail using various mail clients but for some reason I get an authentication error when I try to connect via ...
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1answer
26 views

How to set the username and password for smtpd in Postfix?

I've set up Postfix as SMTP server by adding this configuration to main.cf: myhostname = foo.com mydomain = foo.com myorigin = $mydomain smtpd_sasl_path = private/auth smtpd_sasl_auth_enable = yes ...
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0answers
43 views

Setting up reverse DNS correctly and testing it

I have a mail server which I setup reverse DNS on an Azure service. The IP of the server points back to email.example.com which is what I set it to. I also set my local host name and welcome message ...
2
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2answers
86 views

How to set up TLS on hMailServer?

Complete noob here. Please be gentle :) I have a Windows 2008 server, running hMailServer. Right now all my communication is unencrypted. I want to start using TLS. So now I've got myself a SSL ...
0
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2answers
41 views

sendmail: why the error codes from error:nouser and no user differ?

With sendmail 8.14, when there is no user at a given domain, the error that sendmail seems to produce is as follow: 550 5.1.1 <info@example.su>... User unknown However, if you use the ...
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2answers
85 views

How to enable CentOS 7 to connect to an external SMTP? [closed]

I have a web application deployed in a webserver, running on a CentOS 7. This web application sends e-mails through an external SMTP (in-v3.mailjet.com, port 587). How can I enable CentOS to connect ...
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1answer
50 views

Will exchange server receive emails with wrong address [closed]

Say if I sent an email to user@theirdomain.com, the exchange server and the user will receive it, but if I sent an email to fakeuser@theirdomain.com using SMTP client, there will be no fakeuser ...
2
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0answers
39 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 ...
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1answer
120 views

Postfix STARTTLS only on port 25

I want to enable STARTTLS on port 25, but for unknown reasons it only works on port 465. master.cf: smtp inet n - - - - smtpd -o syslog_name=postfix/smtp -o ...
0
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1answer
75 views

SquirrelMail showing empty inbox. THIS FOLDER IS EMPTY

I have installed postfix, dovecot and squirrelmail. I can send messages and also receive messages. But in Squirrelmail web interface i can see only sent messages it is not showing the mails which are ...
0
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1answer
130 views

Getting a [550 5.1.1 Recipient not found] (Can't receive email) with CloudFlare

I'm having troubles with my email account. I'm using GoDaddy's Email service and the domains that are not connected to CloudFlare are operating just fine. The problem comes in with the domains that I ...
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1answer
26 views

postfix configuration and Received from

Having some trouble here. My server has 3 IP addresses and this is my /etc/hosts: 127.0.0.1 localhost 46.38.235.226 brian.smares.de brian 46.38.238.199 stewie.smares.de stewie 46.38.238.137 ...
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1answer
62 views

Relay denied (454) [closed]

I make test with the website mxtoolbox.com with my smtp and received this error: 220 hostname.example.com ESMTP [702 ms] EHLO MXTB-PWS3.mxtoolbox.com 250-mail.example.com 250-PIPELINING 250-SIZE ...
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2answers
74 views

Internal SMTP server no longer delivering to Google Mail

Our corporate email is hosted on Google Apps, along with 5 domains for various products. Internally (Behind our firewall, not exposed to the internet) we have an IIS server running Microsoft ESMTP ...
0
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0answers
16 views

How do I edit a signed or encrypted SMIME message to include a footer?

Is there any way to edit a signed/encrypted SMIME message so that there is a legal disclaimer on the message? I'm thinking about the MIME multipart email directive may allow for this.
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0answers
42 views

gandi sendmail tls slow

I set up a Debian with Sendmail && SSMTP to be able to send mail through my Gandi Mail Account. It works fine, except that the authentication took like 5 seconds to be established which can ...
1
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2answers
83 views

How to block IP addresses from port 25 [closed]

PROBLEM: Users are getting 15-20 SPAM emails per hour, even with SpamAssassin set to its most aggressive settings SOLUTION: SPAM filtering services are available from companies like McAfee (Intel). ...
2
votes
1answer
34 views

Catch incoming email and then deliver to original recipient on sendmail

in the company I work for there are a user that is making bad use of the email, but to have evidence of what he is doing we need to intercept all the incoming email to him and all outgoing email from ...
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votes
1answer
25 views

Connecting SMTP externally

I have got a local smtp server to relay to Google smtp so as to increase the limit of email recipient from 2,000 a day to 10,000 a day for specific users. I can send through this local smtp ...
2
votes
1answer
49 views

SMTP DNS Validation with multiple mail servers behind multiple Public IPs

I know when a Mail server receives an e-mail, it performs a "DNS 3 way check" (I think this is also sometimes called FCrDNS) as a simply test against spammers. The way I understand it to work is as ...
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1answer
200 views

SMTP Error (451): Failed to add recipient. Temporary lookup failure

Installed iRedMail on Debian Server Can Login to Roundcube Sending Mails from Roundcube results in the following error: SMTP Error (451): Failed to add recipient "XXX@mydomain.de". Temporary ...
2
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0answers
144 views

IIS 6 SMTP unable to relay messages to Exchange Online

Our company uses Office 365 and our email is hosted on Exchange online; however, we have several applications which are unable to send messages directly to Exchange Online due to various reasons ...
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2answers
307 views

GitLab not sending mails

I have a Linux Ubuntu 14.04 installed on my VM. Recently I have installed GitLab 7.8.2 using the instructions on GitLab site, and encountered problems in making Gitlab to send mails. for example, ...
-1
votes
1answer
57 views

postfix apparently relay email

I have read as many documents as I could understand about tuning postfix main.cf parameters, but still get some external email relayed. Here is a typical example in /var/log/mail.log: Mar 6 06:26:13 ...