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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119 views

SMTP proxy (relay) with SSL

Short question I need some kind of SMTP proxy server which does not verify passwords and directly pass credentials and data to a target server. The target server uses self-signed certificate so I ...
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1answer
74 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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197 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
85 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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24 views

Windows server | HmailServe | Relay

My setup: I am using PHPMailer (smtp) to send out emails via my websites. I am using a windows 2012 server as my mail server which is using Hmailserver. I am using Mailgun to relay my emails. Things ...
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1answer
297 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
763 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
102 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
43 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
45 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
348 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
238 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
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1answer
210 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
153 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
182 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
27 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 ...
3
votes
3answers
393 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
110 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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0answers
184 views

Use nginx as reverse proxy for outgoing mail

We have a production server running a singlepage web-app and a separate proxy server, for security reasons. Every request to our web-app is handled by our reverse proxy (nginx) on the proxy server. So ...
0
votes
1answer
24 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
43 views

Postfix acts as sender for unathenticated connections on port 25 for $relay_domains

My postfix can be set as SMTP server on any email client, on port 25, no auth, to successfully deliver e-mail to any domain listed in $relay_domains. This is bad, and can be easily used to send spam ...
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1answer
44 views

Exchange server relay [duplicate]

I'm currently trying to configure our exchange 2010 to be used as a external smtp relay. What I'm trying to do is allow certain websites that we manage to send email using our exchange server smtp ...
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1answer
89 views

How to configure exchange 2010 to be used as an external smtp relay? [closed]

I'm currently trying to configure our exchange 2010 to be used as a external smtp relay. What I'm trying to do is allow certain websites that we manage to send email using our exchange server smtp ...
0
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1answer
413 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
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2answers
557 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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1answer
115 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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1answer
42 views

Postfix: Handle different sender

I have currently the following Setup: Incoming E-Mails: Customer A -> Mailserver of Customer A All other Customers -> Default Relay For Outgoing E-Mails, I set up the sender_dependent_relayhost ...
0
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0answers
30 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
36 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 ...
2
votes
1answer
190 views

sendmail foward local mail to relay host

I have read up a lot on the subject but sadly cant get it to work. I have a Centos 6.3 with sendmail installed. The box gets used as a BackupPC server and maybe a samba server later. I want to ...
-1
votes
1answer
4k views

postfix RCPT TO Temporary lookup failure 451 && mail transport unavailable [closed]

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 ...
2
votes
3answers
184 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
433 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
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1answer
134 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
2k 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
446 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
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0answers
24 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
27 views

Default Relayhost and custom relayhost for domains [closed]

I have a customer which needs a custom relayhost for sending emails. So I want to choose this relayhost only for this domain. customer.example.com -> relayhost A (all other domains) -> relayhost B ...
0
votes
1answer
87 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
419 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
30 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
1k 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 ...
0
votes
1answer
253 views

sieve redirect to foreign email gets “Relay access denied”

I have a postfix mail server with sql authentication and I want to implement sieve on it. Sieve is working relative good, rules who contain 'fileinto' are executed perfectly. I configured a rule in ...
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votes
1answer
109 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
76 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
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1answer
218 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 ...
1
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1answer
314 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
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0answers
367 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 ...
-1
votes
2answers
715 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 ...
-1
votes
2answers
3k views

“Relay access denied” when sending email via php mail in zpanel [closed]

I have installed zpanel on my centos server i am using php mail function to send signup email to my clients. it was working fine on my virtualmin server but when i moved my site to zpanel server it is ...