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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23 views

Try to relay form one domain to second via third

I'm configuring my sendmail mail servers on debian and i have problem. I have two mail servers with domains a.com and b.com, a.com is main server for b.com and all mails going from and to b.com must ...
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2answers
24 views

E-mail reputation using our domain as the from sent by e-mail marketer

My boss wants to send a marketing e-mail to a large group of our customers. I personally feel that it's outside of our core business and don't support it, but that's about all I can do. Normally the ...
0
votes
0answers
14 views

cPanel/EXIM re-routing mails through Mandrill to circumvent Gmail rate-limit

I have two cPanel domain (lets assume abc.com and xyz.com) where we have 300+ mailboxes. Users email themselves and outside the company. Most of the emails sent outside the company are to GMAIL. ...
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0answers
32 views

msmtp error: cannot locate host smtp.gmail.com

First question on this site! Recently, I installed msmtp and mutt on our server for sending email notification about many things. I have worked fine for me for a week but yesterday I found msmtp ...
3
votes
0answers
23 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. ...
0
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0answers
30 views

How to connect ubuntu to external smtp on port 587?

I have a fresh ubuntu server installation with no firewall and want to setup ssmtp to an external smtp server (e.g. smtp.mandrillapp.com:587), however, I couldn't get my server to connect to any ...
0
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0answers
25 views

Dovecot Relay Access Denied; The SMTP server does not recognize any of the authentication methods supported by Entourage

I have a Dovecot/Postfix installation running, and have set up some email accounts using Vimbadmin. I have successfully set up several clients successfully using SSL to both send and recieve. ...
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0answers
38 views

Postfix 25 no route to host [on hold]

I can't configure my postfix. My ISP didn't block 25 port, but in /var/log/maillog I receive this output: Nov 18 21:58:47 hostname postfix/smtp[21530]: connect to ...
2
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1answer
30 views

Exchange 2010 SMTP Pipelining support not working correctly

Am trying to configure a Sophos Appliance (SEA) to handle anti-spam. Part of this service is recipient validation, which interrogates the downstream MTA, in our case, Exchange 2010, for a valid ...
0
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1answer
37 views

Getting unknown mail requests on my SMTP server

I set-up a private mail server on my VPS. I get a lot of mail request on the SMTP server while I did not send them by myself. I disabled the bounce mail to prevent spamming other mail addresses. How ...
0
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0answers
13 views

AmazonSES + DKIM + Hotmail = temperror

Although SPF is passing, I'm getting a dkim=temperror on hotmail only (it's working on Yahoo and Gmail). I'm using AmazonSES, and already have the proper CNAMES for DKIM signing on my domain at ...
3
votes
0answers
57 views

What's the proper way to setup a domain name to not accept email?

RFC 5321 sec. 5 states that: SMTP clients must look up for an MX record; if no MX record for domain is present, look up for an A Resource Record (RR), and if such record is present, treat it as an ...
0
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0answers
59 views

GitLab can not send email correctly through public SMTP server

I installed gitlab on ubuntu 14.04 server following official instruction. I want to send email to new users using public mail server, like gmail, 163, qq. However gitlab can't send email successfully ...
0
votes
1answer
53 views

how to send email from an instance without using sendgrid? [closed]

My project up and beta running on google compute engine. I want to set-up email server. For that i followed http://www.krizna.com/centos/setup-mail-server-in-centos-6/ I edited /etc/postfix/main.cf ...
0
votes
2answers
67 views

CentOS 7 ec2 smtpd - Client host rejected: Access denied

I've been trying to figure this out for hours and can't quite wrap my head around it. I have a mail server on an ec2 instance running CentOS7 that has postfix, courier (authlib and imap), sasl, ...
0
votes
1answer
18 views

Iptables SMTP re-routing on a proxy

I'm lost... Any help would be appreciated :) I have a mailserver. Unfortunately, the provider deny the smtp 25. I don't want to use ESMTP or a vpn. So here is the project : I have a dedicated server ...
0
votes
1answer
18 views

How to make exim4 on Debian safe?

I am running exim4 on a vanilla Debian Stable system. The machine has proper DNS A and MX records. I want to use it as a mail server. SMTP with TLS already works fine for authenticated users. ...
1
vote
1answer
22 views

Does SendMail Support TLS Certificates With Subject Alternative Names?

CentOS 5.x Does SendMail support TLS certificates with Subject Alternative Names? I have a set of sendmail servers and would like to use the same certificate for all of them (to save time and ...
3
votes
1answer
289 views

Does closed Port 25 cause mail to be marked as spam?

I have a web server where I have installed Postfix for sending emails only. All incoming mails will be handled by google apps and not my web server. Using iptables rules, I have blocked all incoming ...
1
vote
2answers
50 views

Postfix login mismatch sender address rejected

I'm getting the following rather annoying error message: Sender address rejected: not owned by user subscription@****.ca; from=<subscription@****.ca> to=<webmaster@****.ca> proto=ESMTP ...
2
votes
1answer
53 views

Centos SMTP error command not implemented

I have a vps with Centos 6.5 and postfix installed. When I want to connect to a smtp server like google or mail gun, I get the error 502 command not implemented. Can anybody help me please? This is ...
2
votes
1answer
43 views

Postfix SMTP server gets “550 Requested mail action not taken: Invalid IP”

I have a SMTP server named smtp-ca.mdpi.com and when sending emails to some specific chinese email domains, I am getting back: 550 Requested mail action not taken: Invalid IP<64.15.147.140> (in ...
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2answers
34 views

Postfix and access restrictions for unknown clients

I'm trying to configure a postfix mailserver and I have a doubt related to parameters like smtpd_reject_unlisted_sender and that sort of things. Of course, I would like to configure my server in such ...
0
votes
1answer
18 views

sending e-mails via sendmail using virtual-users

Currently my sendmail send e-mail with following header: Received: (from www-data@localhost) I want this header to be like: Received: (from contact@mydomain) but I am also hosting multiple ...
2
votes
1answer
63 views

Postfix + Php Mail() VS Postfix + SMTP

Most CMS (Joomla for example) comes with php mail() as default and has the option of changing it to SMTP if we want. I will be setting up both the webserver and mail server (Postfix) in the same VPS ...
2
votes
0answers
35 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 ...
0
votes
1answer
16 views

Make exim4 only send mail, do not make it receieve mail

We send email locally using exim4, but we use Google Apps to receive our email. Unfortunately, exim4 is not sending mail addressed for our domain (internal notifications) to the Google Apps mail ...
0
votes
1answer
117 views

SMTP server, remove port 25 for relay communication

I have setup a SMTP server in my internal network, but I want to remove the port 25 completely since my service provider limits access to port 25. However, even using port 587 in my server to ...
0
votes
2answers
48 views

Rate limit exim per user basis

How can I implement "rate limit" in Exim so that every user in my exim can send specific number of emails per day. List A of Users can send 100 emails per day and the list B of users can send 500 ...
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votes
1answer
48 views

Secure postfix smtp from spammer

I run on Centos 5 with Parallels Plesk 12 and look for to secure my smtp server. When I watch at log, I see some strange line like that, which I supposed it's hack connexion. Has someone any idea on ...
0
votes
0answers
17 views

Exchange 2013 Outlook “Send to cache”

Having some trouble with users changing AD accounts but their primary SMTP address is moved to the new account. Let me explain: User Andersson1 gets a new AD accout because he changes department and ...
0
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0answers
17 views

IronPort, DLP and SMTP integration

We have configured IronPort, DLP and SMTP in my organization. Now I am getting an error message: statin - : TLS handshake could not be completed". Questions: Can anyone please tell me whether ...
0
votes
1answer
253 views

postfix RCPT TO Temporary lookup failure 451 && mail transport unavailable

i configure Postfix and dovecot in fedora 20 my problem is when set RCPT TO return me 451 4.3.0 <test@example.com>: Temporary lookup failure my postfix Configuration main.cf # postfix ...
0
votes
3answers
75 views

How to isolate Google Gmail SMTP server IPs directly?

I am performing some custom routing with a VPN in the mix that is requiring me to add each Google Gmail SMTP server IP to the routing table so that they pass over another gateway than the VPN's ...
0
votes
2answers
95 views

Sending Email by SMTP IIS7.5 via php site

After my company decided to change the website we switched from old ASP.NET site to new website created in Drupal(php). The site is running locally on IIS7.5 and we also have virtual SMTP server on ...
0
votes
1answer
34 views

Exchange 2010 not receiving some emails

Exchange 2010 not receiving emails from some senders. They receive the following email rejection message: Diagnostic information for administrators: Generating server: mail.domain.com.au ...
0
votes
1answer
357 views

Zimbra doesn't send mail via smtp relay anmore

our Zimbra-Server isn't working for outgoing external mail since yesterday. Friday I installed some updates (for shell shock and Kernel updates), restarted and it worked fine. But since yesterday ...
0
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0answers
128 views

Exchange 2013 (CU6): Can't find named Receive Connector referenced in Event ID 1018

I'm receiving the current Event ID's 1018 on an Exchange Server 2013 (CU6) CAS/Mailbox server causing all received/incoming mail, for all users to be stuck in the mail queue (mail is received from an ...
0
votes
0answers
16 views

Monitor outbound SMTP Xen node

Using Xen-PV on one of our nodes, looking for some suggestions on how I can monitor anyone sending mass outbound emails. May be using Tcpdump?
0
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1answer
58 views

Postfix SMTP authentication [duplicate]

I used this guide to create a mailserver for a small business: https://workaround.org/ispmail/wheezy. IMAP is working perfectly but i ran into an issue with SMTP and Authenticated SMTP. When i use an ...
0
votes
1answer
157 views

Postfix wont send mail to external email addresses listed in virtual_alias_domains

We have our main server at mail.mainserver.com with the catchall address catch@mail.mainserver.com We also have two other domains: domain1.com and domain2.com which are hosted at gmail. Gmail is ...
0
votes
1answer
23 views

Reliably identify sender in Exchange SmtpReceiveAgent

I use Exchange as a simple SMTP server and I want to take specific actions depending on who the sender is. I made a connector which allow basic authentication (auth login) and a SmtpReceicveAgent. I ...
0
votes
1answer
225 views

Postfix SMTP Server fails to send messages to anyone outside the domain

Here is the result of a recent test on my SMTP server, I just want this server to send emails which used to work perfectly upto about a week ago Resolving hostname... Connecting... SMTP -> FROM ...
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votes
1answer
39 views

Sendmail emails going to spam [duplicate]

I have sendmail installed on CentOS 6 and whenever I try to send an email, it goes to spam on the recipient. (Gmail in this case) OK, so, the domain I was to send mail on behalf of is: scalpello.info ...
0
votes
1answer
67 views

Postfix config for backend webservers behind a load balancer [closed]

I've two web servers (ws1.example.com, ws2.example.com) with postfix installed locally as a mail rely (using mandrillapp), user access them via www.example.com, which is a load balancer On ws1, the ...
0
votes
1answer
86 views

Sendmail's MTA, MDA and SMTP 550 User Unknown forwarded to postmaster

I have two boxes running sendmail and configured as: MTA accepting connections from the outside world (mta.xyz.com) MDA accepting connections from internal network and storing them in user mailboxes ...
0
votes
1answer
90 views

Postfix: use relayhost only when direct delivery not specified

I read up on using relayhost with Postfix 2.6.6. It's possible to use different relay hosts, with different credentials, for different senders. But how do I use direct delivery with specific senders ...
1
vote
0answers
125 views

vCenter Server Appliance email's not reaching smtp server

Email's being generated from my test alarms in vCenter are not being forwarded to the proxy / SMTP server configured. I run tail -f on the mail log file when generating a test alarm and I can see the ...
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votes
2answers
215 views

“Connection to host lost” on telnet to port 25 [closed]

i installed smtp4dev to test receive mails in my localserver(xampp) for the registration form here: https://github.com/panique/php-login note: localserver is on port: 8080 my php.ini file for SMTP ...
0
votes
1answer
53 views

Client host rejected: cannot find your hostname + SMTP

I have a VPS configured with dovecot. Now for some of the mails that I send are rejected with the following error: Any Clues?