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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60 views

Configure email SMTP Server on Apache2 [closed]

For a while we decided to use another Server (VServer "B") for our Mailserver. I transfered all email accounts and mailbox from VServer "A" to VServer "B". VServer "B" runs well and the clients are ...
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74 views

hMailServer SMTP installed in LAN, clients in LAN can send Email but clients from the Internet cannot

I had checked the troubleshooting guide and many posts here and could not find solution so far. I had setup a network in Azure Cloud with 2 VMs, 1 of which is domain controller and the other is Web ...
3
votes
1answer
80 views

SMTP errors with iOS devices

I'm trying to diagnose why when an iOS device like an iPhone or iPad is set up to use email with our server for the first time, these errors occur. We choose "Other" from the initial set of choices ...
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1answer
21 views

RFC5321 “receiver should check […] reply code” (why?)

In SMTP commands are sent by the sender and responses which all begin with a numeric code are sent by the receiver. but then there's this bit: RFC5321 sec4.2 Whenever possible, a receiver- SMTP ...
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1answer
131 views

postfix multiple IP SMTP banner

I've installed postfix 2.11.3 and we have multiple IP addresses on our server which we want to host two domains, isolated and running on their own IPs. domain1 unix - - n - - ...
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2answers
81 views

How do I configure Postfix to accept SMTP for local users with “@” (at sign) in logins?

I have an Ubuntu 14.04 server at mydomain.com with a bunch of users with @domain in login, like us.er@mydomain.com. Each of them has an "pseudo" account us.er-mydomain.com with the same uid, passwd ...
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1answer
52 views

Exchange SMTP authentication issue with spammers

I have a single Exchange 2013 server with all the roles and it looks like it's being used by a botnet. It is sending mails every 10 minutes to a specific domain from a specific user. It is not an ...
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0answers
51 views

CentOS/sendmail = How to prevent emails from getting “defer” when sent from php mail() function? [duplicate]

I am working on a server running on CentOS (goDaddy VPS). I have WHM setup on it. And I am getting a lot of delays in emails being sent from php's mail() function. I am looking at the Email > Mail ...
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1answer
38 views

iPhone SMTP Server errors with Regional Cell Carrier

I run an email server (CommuniGate Pro) under Red Hat Linux for our organization of about 200 employees. Many of our employees use their phones (iPhones 5 or later), to get their email. Some use IMAP ...
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1answer
46 views

Rewrite sender when relaying to provider server [duplicate]

I am trying to relay email thru my provider that has a mail server for my domain (xxxx.com). My postfix is configured as follows: relayhost = [smtp.xxxx.com]:25 the server requires authorization, ...
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18 views

Can't connect to any SMTP server from neither of the Macs in the network

For a few days now we have been unable to send out any E-mails from various Macs in the network to various SMTP servers. No changes to any hardware or software have been done in the recent time that ...
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1answer
76 views

ERROR: account.INVALID_ATTR_NAME (invalid attr name: invalid attr name) - zimbra

I followed this link to configure outgoing SMTP mail for Zimbra. In the step zmprov ms <server> zimbraMtaSmtpSaslPasswordMaps lmdb:/opt/zimbra/conf/relay_password zimbra show me the error's ...
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2answers
31 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 ...
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0answers
147 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. ...
3
votes
0answers
32 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. ...
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1answer
80 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 ...
2
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1answer
53 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 ...
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1answer
58 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 ...
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135 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
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1answer
77 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 ...
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1answer
129 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 ...
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2answers
311 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, ...
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1answer
50 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 ...
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1answer
28 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. ...
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1answer
29 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
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1answer
323 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 ...
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2answers
122 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
107 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
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1answer
92 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
70 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
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1answer
22 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
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3answers
198 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
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0answers
58 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
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1answer
20 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 ...
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1answer
199 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 ...
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2answers
177 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
78 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 ...
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23 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 ...
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25 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 ...
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1answer
1k 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 ...
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3answers
131 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
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2answers
223 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
80 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
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1answer
792 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 ...
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0answers
264 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 ...
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21 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?
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1answer
72 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
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1answer
283 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
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1answer
24 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
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1answer
484 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 ...