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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Forwarding emails to external domains - aliases vs mda sieve script?

There are 2 points in the flow of a incoming email where emails can be forwarded: As soon as aliases are expanded (setting the target email as alias target) As soon as mails are handed over to the ...
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23 views

Why would an SMTP client send a RSET (Reset) command?

I’m trying to understand how exactly an email is processed by Postfix – and some of the finer details of SMTP mail transactions. My short-term goal is to debug a proprietary (binary, closed source) ...
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0answers
12 views

IIS 6 SMTP service stops working after server restart

I'm currently wrestling with IIS6 SMTP service not working properly when the server is restarted. This has only just started happening in the last month and struggling to pin point the issue. I ...
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1answer
17 views

SMTP server for testing purposes with a few specific requirements [on hold]

As our company started doing development work on their on-line product they used a gmail address for testing purposes, using '+' notation to deliver all test e-mails to a single mailbox. Over time ...
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2answers
32 views

Postfix spam abuse [duplicate]

I have a terrible problem, my joomla website is being abused to massively send spam. I have no clue on what is actually happening, but my postfix mail queue is constantly filled with thousands of spam ...
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0answers
37 views

CentOS Postfix/Dovecot status deferred conversation with 127.0.0.1[127.0.0.1] timed out while receiving the initial server greeting

Linux Kernel: Linux 2.6.32-504.16.2.el6.i686 on i686 RAM: 6GB OS: CentOS 6.6 Postfix 2.6.6 Dovecot 2.0.9 Relay Host Verizon Stunnel through 127.0.0.1:2525 Webmin 1.750 Virtualmin 4.17.gpl Multiple ...
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votes
2answers
48 views

How to install a Mail Server on your Windows Server [closed]

I am looking to move my hosted site + email onto my Azure VPS (Windows Server 2012). I can migrate the site successfully using the @ A Name Record, but how would I go about the email? Do I need to ...
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1answer
16 views

Exchange 2007 - SMTP Traffic

I've done a check of what SMTP trafic is being routed through a 2007 mail server, which we are decommisioning. It looks like all printers are using the mail server for smtp relay, would it be ...
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1answer
34 views

Postfix + php translating email addresses sent to local domains to something@localhost.localdomain [closed]

My first question here, if I don't provide sufficient info straight away, please take it easy on me with the downvotes ;-) I'm running a VPS hosted by afterburst.com with OpenVZ I installed and ...
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2answers
23 views

Mail delivered via server IP not associated with sender

When a sunbirdinc.com account sends an email to an earthlink.net address, the following message bounces back: ToSomeone@earthlink.net host mx1.earthlink.net [209.86.93.226] SMTP error from ...
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2answers
101 views

Relay access denied (in reply to RCPT TO command) Postfix Issue

I am trying to configure my server for email taking reference form this link: SMTP Relaying Outgoing Mail in Postfix - using Webmin. I used Mandrill smtp server in my case. I have also configured a ...
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1answer
52 views

Postfix mandatory smtp/smtpd vs “not mandatory” difference and configuration

Three questions: Correct me if I'm wrong: smtpd_tls_mandatory_ciphers => settings for incoming mandatory TLS encryption smtpd_tls_ciphers => settings for incoming opportunistic TLS encryption ...
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0answers
16 views

configure sendmail to discard inbound mail sent in error

Management has asked that I set up a sendmail rule to not respond to internet mail sent in error. I think this can be done through ruleset hooks, where an address resolving to $#error can be routed ...
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2answers
37 views

SMTP Reverse DNS Mismatch Reverse DNS does not match SMTP Banner

I wonder if you could help me? I have set rDNS to mail.simplyislam.biz for IP 178.32.48.104 with my hosting server and also in DNS control panel. However, I am still failing this test: ...
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3answers
37 views

How to force Postfix SMTP to use AUTH (SASL?) and reject anonymous connections? [closed]

The following snippet has been added to the main.cf file of postfix: smtpd_sasl_auth_enable = yes smtpd_sasl_security_options = noanonymous smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd ...
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0answers
17 views

Need help setting dynamic message-id in headers

I am using software to send newsletters to clients. The software is connected to an SMTP server, which is configured correctly. The issue is the email software I am using does not merge/transfer ...
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1answer
17 views

Exchange 2003 restrict anonymous smtp access only

On exchange 2003 I want to listen for smtp on port 25 only so that * anonymous login is only allowed from certain internal IPs * authenticated login is allowed from everywhere I can't see how to do ...
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1answer
29 views

SMTP service detection

I have some basic questions regarding SMTP connections, particularly for Postfix but would appreciate advice for MS Exchange too: When a single relay for a given remote domain becomes unavailable, ...
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0answers
13 views

Windows Server 2008 IIS6 SMTP With more than 1 FQDN

I've tried researching this one, but I'm not having much luck on google. What I have is a Windows Server 08 R2 with IIS6 SMTP installed and configured / working 100% perfectly for Domain A. Domain ...
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0answers
10 views

FreeBSD pf does not allow inbound smtp [duplicate]

I'm trying to figure out why the following simple pf config allows inbound SSH but not smtp (tcp 25). I'm running FreeBSD 10.1-RELEASE-p9, and the SMTP server is postfix 2.11.4. # ...
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0answers
18 views

Server apparently being exploited to send emails [duplicate]

I have a dedicated server which runs a forum, a couple of wordpress installations and a prestashop ecommerce platform. My datacentre keeps cutting my connection, stating that my server is sending out ...
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0answers
81 views

php mailer SMTP ERROR: Failed to connect to server: Permission denied (13)

I fixed this error on a dedicated cPanel server by allowing outgoing connections on port 465 on iptables. I'm trying on AWS now, but I can't figure out what's wrong. I stopped SELinux and iptables; ...
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2answers
84 views

PostFix 550 5.1.1 Recipient not found from external email

This is a new installation. PostFix reports "550 5.1.1" "Recipient not found.", when users exist. User can send email out everywhere. Users can send email to each other through localhost. All ...
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votes
3answers
78 views

Reject incoming emails that use your own domain as sender

It would be nice to reject incoming emails which use one of my virtual domains as sender address while not being a legitimate user of mine. I know that I can reject incoming emails which use an ...
3
votes
1answer
120 views

postfix: forward all mail except local user ones

I have a website on a server with a postfix mail server to send the site's emails. Let's say the domain is example.com. The site can send mails to mailboxes of his own domain (like ...
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0answers
62 views

SMTP error : Remote host said: 550 5.7.1 At least one FROM header address not allowed to send mail from IP ADDRESS

We are developing an email sending app, and we allow our users to specify the From: header their emails will be sent from. Let's say our domain is mydomain.com and our client domain is ...
2
votes
1answer
52 views

Postfix : Conditional Header Checks

Here is my SMTP situation. Mail flow is tagged by an online relay provider (!!SPAM!!, !!BULK!!, etc) Mail flow is received by an internal postfix. Transport is configured to relay to our internal ...
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1answer
77 views

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 ...
4
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2answers
105 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 ...
3
votes
1answer
46 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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2answers
58 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 ...
3
votes
1answer
24 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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2answers
44 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 ...
0
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1answer
14 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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votes
1answer
57 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
votes
1answer
49 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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votes
1answer
52 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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votes
3answers
80 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
50 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
votes
1answer
90 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 # ...
0
votes
1answer
58 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 ...
0
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0answers
23 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 ...
1
vote
1answer
55 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
79 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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1answer
59 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
166 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
53 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
63 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
votes
1answer
46 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 ...