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

-2
votes
1answer
31 views

SMTP Server with dynamic / Static IP

I have 3 servers and 3 IP's. Server 1 - Static IP - 111.111.111.111 Server 2 - Static IP - 222.222.222.222 Server 3 - Dynamic IP - 333.333.333.333 Now Server 3 is always assigned the IP ...
0
votes
0answers
53 views

cant send to gmail. Remote host said: 421 4.7.0 Senders Guidelines

I have a SMTP account by hostgator. It has been working OK for a few years. in the last week all emails sent to gmail accounts are bounced with the following message: Could not deliver message to ...
1
vote
0answers
113 views

Postfix “Connection timed out”

I try to send a few emails, but postfix send only 3 emails every 10-20 min. After that postfix sends 3 emails, I get the error: "Connection timed out". mail.log: Jan 4 12:16:39 mail ...
1
vote
0answers
46 views

How to detect SMTP AUTH attempts in Fail2Ban?

I have a Fail2Ban jail that monitors failed SASL authentications to my Postfix SMTP server. When this occurs, /var/log/mail.log contains these three lines: postfix/smtpd[32591]: connect from ...
0
votes
0answers
28 views

Incoming SMTP to Azure Windows VM going to C:\inetpub\mailroot\Queue\ instead of Drop\

I have an ASP.NET web app that needs to process incoming SMTP email from any Internet user. I configured IIS and my Azure Windows server 2012 R2 VM end point, but when I send email from the Internet, ...
0
votes
0answers
74 views

Trying to set up Gmail “send mail as” SMTP mail function

Alright, so I've come here as a last resort hoping to find that last bit of help I need to solve this. I've spent the last two days scouring for answers without actually getting anything direct. First ...
0
votes
1answer
36 views

how to stop incoming SMTP .EML attack on an Azure Windows VM

This morning 1:53am, my Azure VM began receiving unexpected .EML files in C:\inetpub\mailroot\Queue. By about 6am when I first logged on, it had received over 36000 files. As a workaround, I stopped ...
1
vote
2answers
44 views

How to find out who is sending email

I have a server which doesn't have much activity. Today, suddenly server load went higher than 12 which compared to its normal value(0.5) is way too high. I checked and found out that postfix is being ...
-3
votes
1answer
62 views

SMTP (postfix) and iPhone - can't send emails - reject: RCPT

I try to setup email server already 2 days, everything work flawless when i use roundcube on PC, I can send and receive emails, but problems start when I want to setup my email on iPhone. I can ...
-1
votes
1answer
30 views

Postfix - Host or domain not found

I installed postfix on my centos. this is postconf -n output: alias_database = hash:/etc/aliases alias_maps = hash:/etc/aliases command_directory = /usr/sbin config_directory = /etc/postfix ...
0
votes
0answers
16 views

How to show email addresses in Outlook 2013 SMTP logs?

I need to troubleshoot some client-side issues while sending SMTP messages using Outlook 2013; I've turned on diagnostic logging, however the sender and recipient addresses are hidden in the logs: ...
0
votes
0answers
18 views

ICEwarp 11 mail server ERROR with relay mail

I have a promblem when i send mail from icewarp to relay server. user1@mydomain.com send a email to xyz@yahoo.com through mail.myrelay.com mydomain server and myrelay server in a DATA ROOM. I can not ...
-1
votes
1answer
39 views

How to configure exim4 for both incoming SMTP for local delivery and relay for authenticated user

I want to use my exim4 mail server as local delivery for anonymous sender for my localdomains, and relay to everyone only for authenticated users. Is it possible?
0
votes
1answer
184 views

How SMTP (receiving emails) works?

I have a very hard time to understand how SMTP works. I've read already: Message Submission for Mail Internet Mail Architecture Internet Message Format Simple Mail Transfer Protocol I know the ...
5
votes
2answers
253 views

How to allow login to a SMTP server better than with password?

I'm planning on creating a mail server, but I don't want to use passwords at all. They seem a wrong security choice to me. I'd love to use a certificate to login. This seems easy to do in HTTP, but I ...
0
votes
1answer
57 views

OSSEC alerts without hosting SMTP

I've been searching without a solid solution yet. I need to send OSSEC email alerts from my OSSEC server, but without hosting an SMTP server (postfix, etc). I get rejected by the Google SMTP servers ...
10
votes
3answers
274 views

MX priority server behaviour

This is a question about MX procotol priority. If I have two server as MX with different priority: MX 10 serverA MX 20 serverB Is this guarantee by the protocol that the MX 10 is the prefered? Can ...
0
votes
1answer
22 views

Remote Postfix server for email relaying multiple domains

I have a local server at home that needs to send and receive email but my ISP blocks port 25 in and out. The local server is running Debian 8, has Virtualmin installed on top of it with postfix and it ...
1
vote
1answer
73 views

Postfix: Set custom SMTP Banner based on domain (same ip) used to access server

I have multiple domains on my server pointing to the same ip address. How can I setup postfix to greet with each individual smtp banner based on the domain name? I've searched everywhere but didn't ...
0
votes
0answers
30 views

DKIM fail signature doesnt verify

I had setup postfix and dkim and keep on getting dkim=fail on port25 and gmail checks. DKIM check details: Result: fail (signature doesn't verify) ID(s) verified: Canonicalized Headers: ...
0
votes
1answer
27 views

SMTP relay for multiple subdomains

here is my situation: I have a few subdomains: x1.example.com, x2.example.com.. IP adresses for these subdomains in local network : 192.168.1.1, 192.168.1.2.. They are not reachable from internet. I ...
0
votes
1answer
21 views

“lost connection after UNKNOWN” (OpenDKIM + postfix receiving emails)

I had a fully working mail server before installingopendkim with TLS with a free StartSSL certificate, that Thunderbird could interface with properly to send/receive email. My distro is Debian 8. ...
0
votes
0answers
21 views

Emails sent by my SMTP Service on Windows Server 2012 going to Spam folder [duplicate]

I'm trying to setup the SMTP Service on a Windows 2012 server (Amazon EC2). I followed this guide for configuring it, and I also added in Godaddy a CName record with the Host "mail" that points to ...
1
vote
1answer
24 views

No control panel equivalent of exim /etc/mailips file for configuring IPs for each domain's outgoing mail?

I have a problem with outgoing SMTP mail being sent with the wrong IP address. I use exim for outgoing mail. I found a guide "How to manually configure Exim's outgoing IP addresses", which suggests ...
0
votes
0answers
53 views

Postfix “ Sender address rejected: not owned by user”

I've setup a Postfix/Dovecot mail server on AWS. I've implemented self-signed TLS authorization, connected to it from and external TBird client and tried to send/receive email. TBird is able to ...
0
votes
1answer
25 views

What is “mail._domainkey” and why would it be a DNS “TXT” record with a string “k=rsa; p=[base64]”?

I added some new IP addresses and domains to a VPS (Centos) managed with Vesta Control Panel. Everything seemed to work, but then, a few hours later, I noticed some emails (SMTP) from a previous, ...
1
vote
1answer
20 views

deny an email from sender at one of my mx records, so it tries the other mx record

Does anyone know what SMTP reply code I can give to a sender trying to deliver mail to my server so it knows the mail can not be delivered to my server. But not a hard fail so it bounces the email ...
0
votes
0answers
20 views

Is it possible to modify sender address if I use Windows Server 2012 R2 as SMTP relay?

I am working in a company that only allows email address on the directory to be sent. But for HP iLO alertmail system, it does not allow users to modify the sender address. The sender address is ...
3
votes
2answers
44 views

Internet facing Hub Transport Exchange server with Internet restricted users and a Canon Copier

This is a rather convoluted problem but I hope that someone out there has experienced a similar situation. Here are the facts of what is happening: We have a single Exchange 2010 server that is ...
0
votes
0answers
14 views

How to pass email from intranet hMailServer to Internet server

I have had hMailServer running on an intranet in an industrial application for years without trouble. It accepts email reports from machines and parses them into an SQL database. I now wish to send a ...
1
vote
0answers
87 views

Outlook.com rejects: 550 SC-001 (BAY004-MC5F13)

I am operating a cluster of 3 dedicated machines for a webapp, each of those uses sendmail as MTA. Hostnames are node1.domain.com node2.domain.com node3.domain.com Unfortunatelly outlook.com rejects ...
3
votes
1answer
33 views

Cannot set a default SMTP server certificate on Exchange Server 2013

I've an Exchange 2013 Server with two wildcard certificates, one for matching the internal AD zone and the other one with the public domain. The certificates are defined with those names: ...
0
votes
1answer
37 views

SMTP not reachable

for some time now I am not able to reach SMTP on port 25 or 587 on a server of mine from the outside though both ports are open and postfix is listening on them: $ telnet domain.tld 25 Telnet escape ...
0
votes
0answers
9 views

Relaying for SMTP Virtual Server

On an external server I installed the SMTP Virtual server using this how to: http://www.lukepuplett.com/2010/06/how-to-send-email-from-microsoft-server.html I setup the firewall so localhost and the ...
1
vote
3answers
58 views

How can I find out which script/program/user invokes exim (and is sending spam)?

The problem A client of mine asked me to take a look at his shared-hosting webserver for the following problem, but I'm stuck at finding out what's wrong. His server is being blacklisted by a lot of ...
0
votes
1answer
48 views

How to pass through credentials in SMTP proxy with Postfix

I want Postfix to proxy SMTP connections from MUA on my client to another outer SMTP server. Since the outer SMTP server requires the Postfix proxy to authenticate with SMTP-AUTH, So I set my MUA's ...
0
votes
1answer
28 views

iRedAdmin SMTP sending error

Recently i installed iredadmin on Debian. Then i tried to send mail using laravel framework with SMTP settings, but i cant get the email. This is my mail error log: Nov 26 10:19:43 server ...
0
votes
1answer
63 views

“SASL authentication failed” when authenticating to receiving mail server

Some recipients do not receive emails from my Postfix 2.11.0 server. Their servers reject my SASL connections with errors like 535 5.7.8 Error: authentication failed: authentication failure and 535 ...
0
votes
1answer
52 views

Users allowed to send mail using postfix

I've installed postfix and opendkim on my ubuntu server, intending to use this server as a private relay for an application to send "activation" emails to new users. I configured SASL authentication ...
1
vote
1answer
74 views

sending emails fails with gmail only

My debian server sends email to yahoo, hotmail but not to gmail ! tail /etc/log/mail.log 95.211.117.206], dsn=4.0.0, stat=Deferred: Connection timed out with 75gmail.com. Nov 23 23:07:52 sitechat ...
0
votes
2answers
63 views

exim4 keeps retrying message that fails after “closed connection in response to sending data block”

Let me start by saying that I'm not an IT guy, but I've been pressed into it in my office. Someone at my office sent an 86MB e-mail attachment to someone at aol.com, and aol.com is rejecting the ...
0
votes
0answers
23 views

sendEmail dh key too small

We use sendEmail to interface to customers mail server and send e-mails out of our software. currently I am attempting to authenticate send email against an ATT e-mail account. I keep getting the ...
1
vote
0answers
7 views

Are there issues in whitelabling a SMTP server (not mine) with an A record that doesn't match 200 helo?

I know that a CNAME and a MX record can't exist on the same host. In this scenario I'm using A records to manage SMTP for 350 DNS domains. companyA.com MX myAlias.whitelabel.com companyb.com MX ...
3
votes
0answers
27 views

Is reverse DNS a good method for promoting grey IPs from trusted domains to white?

I'm trying to set up a mail server using OpenBSD, OpenSMTPD, spamd, and pf. The first problem I've encountered is that many large webmail providers - like Gmail - will retry delivery from a different ...
0
votes
1answer
84 views

SMTP HELO command from Windows gives 500 Command unrecognized error, same command from Linux returns Hello

We have a Java web application that needs to send out emails to our users, and I'm getting this Java error when those emails try to go out: javax.mail.MessagingException: Could not connect to SMTP ...
2
votes
2answers
55 views

Is it a good idea to reduce the give-up time for e-mail delivery?

We run an e-mail server for a few customers, and we've recently run into a bit of a conundrum. We had a user who sent an e-mail to an incorrect e-mail address. The incorrectly specified domain ...
0
votes
0answers
35 views

Using postfix to send email in redmine

I'm trying to configure sendmail to send emails from the Redmine installation (which I still haven't figured out how to run with Apache). When I send mails from the terminal, with the command ...
9
votes
2answers
119 views

How can I use wildcards for sendmail TLS_Rcpt?

sendmail lets one place restrictions on TLS conversations. I want to check that messages sent to example.com are sent to a server that has a *.messagelabs.com certificate. I want to protect against ...
1
vote
0answers
30 views

Postfix permit localhost use plain login

I have postfix 2.11 setup on Debian jessie with Dovecot SASL and I require encrypted login mechanism to send mail via smtp. For this purpose in the main.cf I've smtpd_tls_auth_only = yes option set. ...
1
vote
1answer
93 views

Gmail accepting postfix relay via Port 25 but rejecting emails sent via TLS login on same server?

I have a postfix email server that handles mail via two routes. First is a relay on port 25, this is dedicated to a single external IP address via a 'mynetworks' entry. This route is to handle email ...