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.

learn more… | top users | synonyms

-1
votes
0answers
16 views

Cannot use Client SMTP Submission with smtp.office365.com [on hold]

Recently we have successfully migrated our nearly 50 users from On-Premises Exchange 2010 to Office 365. Mail flow is fine, the old server has been decommissioned a couple of weeks ago so we are fine ...
2
votes
1answer
22 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 ...
1
vote
1answer
21 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 ...
-2
votes
0answers
37 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 ...
1
vote
2answers
35 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
votes
2answers
22 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 ...
0
votes
2answers
54 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 ...
-2
votes
1answer
40 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
votes
0answers
24 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 ...
0
votes
1answer
61 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
votes
1answer
32 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
votes
0answers
50 views

postfix/mail: where can I find configuration of SMTP server?

I'm working on an older, pre-configured Linux server (openSUSE 12.1) on which some programs send email via /usr/bin/mail: echo "text" | /usr/bin/mail -s "subject" -r recipient_email recipient_email ...
0
votes
1answer
40 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 ...
1
vote
1answer
20 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 ...
0
votes
1answer
37 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 ...
-1
votes
2answers
57 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 ...
-2
votes
0answers
28 views

why is my email still going into spamboxes? [duplicate]

the domain is ex-mailer.com and gmail and outlook.com are still sending emails to spambox by default. My DNS should be spotless which includes DNSsec http://dnsviz.net/d/ex-mailer.com/dnssec/ I am ...
0
votes
0answers
11 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.
0
votes
0answers
27 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
vote
2answers
58 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
27 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 ...
-1
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
37 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 ...
-2
votes
0answers
19 views

SMTP server for same domain as Google Apps for Business

My company currently uses Google Apps for Business. For our application I need to create an SMTP server that can send out emails. I can't use gmails smtp because it limits the number of emails per ...
0
votes
1answer
104 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
votes
0answers
107 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 ...
1
vote
2answers
142 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
52 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 ...
1
vote
1answer
30 views

SMTP Preprocessing

I want to move our SMTP services in house, but have a major hurdle I need to overcome. Our firewall/content filter has an SMTP mail scanner blacklists, virus etc. The system is supposed to be device ...
4
votes
1answer
118 views

how do I set up two smtp ports for postfix?

A CentOS 7 server with postfix, dovecot, and mailx needs to accommodate mail being sent through port 465 and received through port 25. What specific syntax and files need to be changed in order to ...
1
vote
1answer
58 views

Allowing Postfix Relaying For Certain Hosts [duplicate]

I have Postfix setup in a test environment, segregated from our LAN, and relaying for hosts in the test environment. Originally, I had all outbound email funneling through procmail and into a single ...
0
votes
1answer
25 views

opendkim to sign all '*' users in a domain

How do you get opendkim to sign for all users in a domain? *@exmailer.com exmailmap in the signing table is not working for me. error: opendkim[1565]: 573D4A0D3D: no signing table match for ...
1
vote
1answer
42 views

How to route select e-mails from Office 365 to another SMTP Server

I have set up an SAP system to act as an SMTP server on port 25000. The company uses Office 365 as its email provider. Is it possible to route/forward e-mails that are delivered to a specific e-mail ...
0
votes
2answers
57 views

I am able to receive mails but unable to send via my SMTP server?

I have a shared hosting server from hostgator, in which I created an email 'support@mydomain.com'. Then I enabled both DKIM and SPF (as I read on a few threads that SPF should be enabled to ensure a ...
-2
votes
1answer
69 views

Postfix POP3 NOQUEUE: reject: RCPT error

I am getting an NOQUEUE: reject: RCPT error when trying to send mail via POP3 and Postfix (note: IMAP works fine). Feb 21 06:57:04 r2d2 dovecot: pop3(br@telecomm.com): Disconnected: Logged out ...
1
vote
2answers
95 views

Can't connect with telnet from external ip

I have a postfix server running on a kimsufi VPS, i installed roundcube on it, and everything is ok. The problem is, when i try to connect from another server, i have a timeout : telnet whys.fr 25 ...
0
votes
1answer
61 views

Failed Gmail SPF check when importing mail through IMAP from our mailbox when original email was sent with ESMTP headers

We have a strange situation: we receive an email with ESMTP headers in it our server accepts it, it's fine we import that mail in Gmail like any other emails from our boxes Gmail makes SPF check ...
0
votes
1answer
73 views

How can I configure a Haraka mail server to forward mails to another address on another domain?

I'd like to setup an Haraka mail server on a domain (let's say 'example.com') that will only act as a forwarding service to a 'gmail.com' email address. For the sake of the example let's say I'd like ...
0
votes
0answers
15 views

When using an “Internal Relay Domain” as an Accepted Domain, what email addresses must be synched?

There are a number of SMTP addresses associated with a user in Exchange SMTP, X500, X400, etc. In addition there is a LegacyDN. Some of these email addresses are stored in the NK2 files and also in ...
0
votes
1answer
70 views

SPF records when sending multi-domain emails from one host

We have a CMS system in which multiple customers run their websites from a single virtual machine. Pages generated by the CMS allow forms to be filled in, which trigger emails to be sent. I am having ...
0
votes
0answers
20 views

Is it possible to whitelabel MX records? [duplicate]

I have a domain at example.com. I would like to setup email hosting with Zoho email services. Is it possible to setup imap.example.com to forward to imap.zoho.com? I have tried adding a CNAME ...
2
votes
1answer
151 views

reason: 403 4.7.0 TLS handshake failed

Sending email to one particular domain, I get the following error: ----- The following addresses had permanent fatal errors ----- <> (reason: 403 4.7.0 TLS handshake failed.) ----- ...
1
vote
1answer
44 views

Postfix SMTP recipient filter not filtering

I have setup Postfix with a list of blacklisted recipients, so that the Postfix server should not relay mail to them (smtpd_recipient_access parameter in main.cf). The addresses are properly listed ...
2
votes
1answer
184 views

NOQUEUE: reject: RCPT from on freebsd and postfix

I am building a server using this config -> http://www.purplehat.org/?page_id=4 and when trying to test basic email capabilities I get -> NOQUEUE: reject: RCPT from when try to send a test email. ...
0
votes
2answers
117 views

Email server attack from telnet

My mail server having a problem on blocking some attacker that trying to telnet to our mailserver. but i'm not able to block it, ip will keep changing even we block by ip. seems like he is trying to ...
2
votes
1answer
43 views

Exchange 2010 is trying to relay messages for delivery

I am using Exchange 2010 on premises. I am in the process of setting up a SMTP proxy that will receive all messages coming into the office, log them, then forward them to my exchange server for local ...
3
votes
0answers
104 views

Why Outlook, Hotmail and Live return 250 Mail queued for delivery, but they never deliver it?

Ok, i've been seeing this the last week, tought it could be gone in a few days by itself, since i wasn't blacklisted and my DNS entries are all ok, but when i try to send e-mails to some user at ...
-2
votes
1answer
52 views

Overcome Gmail smtp send limit [closed]

I have a few IP cameras which sends photos to an email address if motion is detected. My problem is that someone times a lot of motion happening and the camera will flood the Gmail smtp server which ...
1
vote
1answer
33 views

Relay Mail from an application to Gmail through ssmtp

i want make my linux server to receive mail from an host (LAN but if possible through Internet) and than relay to Gmail. I made the second part with ssmtp let the server send mail through Gmail using ...
0
votes
1answer
47 views

exim4: queue_run_max: not found

I need to manage the number of outgoing concurrent SMTP connections - other mail servers are complaining that I have more than 50 concurrent connections and throttling my outgoing mail. I googled and ...