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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10 views

How to route selected e-mails from Office 365 to SAP SMTP Server [on hold]

This is a follow up question to the answer posted by @TechBoy: "I ended up forwarding e-mails from one domain to another - using the second domain as an 'SAP e-mail only domain', which would be routed ...
0
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0answers
27 views

smtp-request behind iptables-router not working

I set up a router with ip-forwarding on Ubuntu 16.04 Server edition. I enabled ip-forwarding in /etc/sysctl.conf . I have set net.ipv4.ip_forward=1 and executed sysctl -p /etc/sysctl.conf I used ...
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2answers
27 views

SMTP recipient callout using static sender address

Our mail provider provides the MXs for our domains, performs some screening on the mails (spam checks etc.) and then delivers the mails to our internal mail server. (They use Cisco Ironport.) They ...
0
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0answers
16 views

host smtp-in.orange.fr[80.12.242.9] said: 501 5.1.0 Emetteur invalide. Invalid Sender. OFR004_405 [405] (in reply to MAIL

After upgrading my ubuntu 14.4 with command apt-get upgrade, the php version has been updated to the version (5.6). The result is that our mail service does not work correctly. Actually, some ...
1
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1answer
22 views

OpenSSL No Client Certificate Presented (SMTP, Postfix)

I used OpenSSL to create a private key and self-signed public certificate. I then created a Certificate Authority file that contains both the private key and public certificate (mail.example.com.pem). ...
0
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0answers
12 views

Configure Postfx using external domain

Please tell me, if I have two servers, one does not have a domain name. Can I configure Postfix to send and receive mail at first using a domain of second? And if so, how?
2
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1answer
21 views

Exim fakereject control not working

After following the Exim documentation on ACLs, I cannot get Exim to utilize the fakereject control for the address noreply@other.com with the following config (only relevant lines included): # ...
0
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1answer
16 views

Classic ASP CDOSYS and Exchange CAS server

I'm having an issue where my comapany are migrating our exchange to a new CAS server. We have several pages on our website using classic asp that sends email using CDOSYS which are working fine with ...
1
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2answers
70 views

Hotmail blocks my SMTP server [duplicate]

Recently i discovered that hotmail has blocked my SMTP once again. The error code is Diagnostic-Code: smtp;550 SC-001 (COL004-MC5F28) I only send for my web based online 2d text game : http://www....
0
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1answer
37 views

Sending mail from inside docker container

I am completely new do Docker, and a total n00b to linux, so apologies if this sounds silly. I have gotten a docker system up and running on Digital Ocean, and its working nicely. I am using a pre-...
0
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1answer
41 views

Exim client not issuing STARTTLS when connecting to smarthost

I have a Debian8 server running exim4 that sends outgoing mail by smarthost through NameCheap's mail.privateemail.com smtp server - or at least it use to. After a recent update, the server no longer ...
1
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0answers
18 views

Postfix. Sending some messages using external smtp server and some messages “directly”. Issue with sender_dependent_relayhost_maps

I'm configuring a new web server and i need to make emails from my PHP scripts to be sent. Most messages should be sent using mandrill SMTP and some "directly" from my server to email services. I ...
3
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1answer
38 views

SMTP authentification request transfer to another SMTP

I'm having an issue that's above my competence level. As we're working on improving the security measures that are in place in our network, we found (among others) one flaw that we have no idea how to ...
0
votes
1answer
19 views

How to restrict SMTP login to its own address in sasldb2? [duplicate]

I'm using sasldb2 (without saslauthd) for SMTP authentication with Postfix. To create a new user, I run saslpasswd2 -u example.com mail which creates a login mail@example.com. However, using these ...
0
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0answers
31 views

postfix mails stuck in mailqueue

I ran into a problem, I'm trying to set up postfix mail server (I'm using webmin), everything seems to work fine, I successfully connected outlook to POP3/SMTP, but as soon as I send an email, it gets ...
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2answers
22 views

Is it possible that i use not mail.example.com,can i use just another like abc.example.com for my mailserver? [closed]

Two questions, two problems. I use cloudflare so I don't reveal my IP, there is a problem I can not use cloudflare for my mail server. Now is it so i am under DDOS because mail.example.com is exposed....
3
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1answer
34 views

Why would an MX record have an associated IP Address of localhost?

We are having issues talking to another company. There mails are bouncing back with the error: #< #5.0.0 X-Spam-Firewall; mail for airinuit.ca loops back to myself> #SMTP# I have seen this ...
0
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2answers
41 views

E-Mail delivery mechanism

Background I am working with email headers for spam detection.Each E-Mail header contains many "Received-from" fields,each "Received From" field added by an intermediate Smtp/Mail server in the path ...
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0answers
14 views

operating own smtp server vs using some ESP [duplicate]

my question may seem old but i have to ask this because I did not find anything helpful for my scenario. for my business, i need to send huge number of email daily, more than 200K. i have gone ...
0
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0answers
15 views

sendmail keeps delivering locally only, using SES

I have a strange problem where when I try to send mails with sendmail on my box, they keep getting delivered to my local user every time instead of to the remote, does anyone know why it is being ...
0
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1answer
51 views

Setting up mail accounts without real Linux users

I've setup Postfix and Dovecot on my Ubuntu Server. My aim is to create 27 mail accounts that can receive and send mail to everywhere. I've got emails to not show up as spam in Gmail, Yahoo and ...
0
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1answer
12 views

Configure dovecot using postfix to send email from any email to any email

I am trying to configure smtp server to allow my applications on the server to use this smtp to send email to/from any email address. I have used all the configurations from http://www.server-world....
0
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1answer
50 views

Postfix Mail Server & hosted Gmail relay setup

I am trying to setup our web server so that it can send emails from various web apps to reset password etc. Our mail is hosted by Gmail with a custom domain eg. mydomain.com. Right now emails going ...
0
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0answers
13 views

Nested MTA in postfix in Ubuntu 14.04

I have a machine M1 which is in environment A and another machine M2 in environment B. Machine M1 has access to our mail server. It can send mail to our email addresses by connecting to our mail ...
0
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1answer
113 views

ssmtp settings for namecheap: Invalid response SMTP Server (STARTTLS)

I am trying to configure ssmtp to use the namecheap smtp server to send emails. My current configuration: root=my@email.com mailhub=mail.privateemail.com:465 rewriteDomain=email.com hostname=email....
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2answers
34 views

exchange server incoming mail issue from internet

I have registered a domain under godaddy.com, and I have exchange server 2010. My question is my exchange server can send and receive emails on the same network(local network). I can also be able to ...
0
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1answer
20 views

SMTP Error - Dovecot/Postfix

Both Dovecot and Postfix are working perfectly. Especially for machines Win 8+ and Mac OS 10.10+ as well as iOS 8+. But trying to connect from a 10.9 Mavericks Mac makes it weird... Here is my main....
0
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1answer
106 views

Postfix - restrict authenticated senders to their own e-mail address in MAIL FROM

How do I prevent my (authenticated) users from sending email messages with either incorrect or outright falsified email FROM addresses? My mail service is postfix and I have already set sender and ...
1
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2answers
32 views

sending emails from different Smtps in different IPs

I sent mails with different Smtps for example Smtp1 on IP 1.1.1.1 and Smtp2 on IP 2.2.2.2 . which my spf record for the From (info@myDoamin.com) part in emails is : spf1 include:mail.mydomain....
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1answer
27 views

Which Email Server Expands the Recipient List into Many Emails?

When sending a message via a different SMTP outbound gateway, will a message containing multiple recipients in the BCC field be broken up into many messages by the originating server, or the server ...
0
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1answer
42 views

Windows Server 2012 Telnet connection lost port 25

I am new to Windows servers, I have Windows Server 2012 and I am trying to set up and enable mail server (SMTP). I have followed this tutorial to instal and enable SMTP server and completed it ...
0
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2answers
43 views

Find out exactly what (which php script) is trying to send spam from server

Last night my server was compromised (I guess - one of outdated PHP CMS's) and many spam messages were sent. I have restricted access to Postfix (via authorized_submit_users directive in main.cf) ...
1
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1answer
67 views

External recipients in distribution group not receiving emails

In Office365, we have a distribution group, group@company.com, set up with the following members: internaluser1@company.com internaluser2@company.com externaluser@external.com (@gmail.com, for ...
0
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1answer
30 views

iptables port forwarding to server with different port

I am trying to port forward from one server to another. I have tried numerous iptables commands but they don't work. Am I doing something wrong? Here is my setup: VPS1: 1.1.1.1 SMTP Port : 25 UFW:...
0
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1answer
42 views

Can I retrieve email marked as rejected in the SMTP log?

I am using a Sophos UTM 9 SG210 firewall and noticed in the SMTP log that a formerly trusted sender has had 50 legitimate emails rejected. I've since added them to an exemption list, but was ...
0
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1answer
47 views

courier-authlib: wrong username enters search query

I am trying to setup smtp authentication using courier, mysql on postfix. My passwords in my db are encrypted. When I attempt to connect, I get an auth failure r2d2 ~ # telnet mail.server.com 25 ...
0
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1answer
23 views

How can I enable Django to send emails?

I have a Debian server (Linux www 4.5.0-x86_64-linode65 #2 SMP Mon Mar 14 18:01:58 EDT 2016 x86_64 GNU/Linux), and postfix is installed. It is working at least far enough that if, from the command ...
0
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0answers
50 views

Relay Server settings for Exim to connect through SMTP/Mailgun

What I'm trying to do: Send out Wordpress notifications using SMTP/Mailgun instead of PHPmailer. I have a production VPS with one IP and several Wordpress installs with different domains. It has ...
0
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0answers
19 views

System.Net.Mail, stunnel and SDE interoperability

We have a third party product, SDE, which we are trying to attach to an stunnel to support our modern email servers. This product, I believe, internally uses System.Net.Mail or System.Web.Mail, given ...
4
votes
1answer
160 views

Is there a way to “replay” a packet capture of a smtp session for the purpose of debugging?

I'm troubleshooting a smtp issue involving character-set encoding and it's extremely difficult to involve the end user. I have a packet capture of an incoming smtp session that results in problematic ...
0
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1answer
10 views

What does sendmail need to specifically see in order to determine if a remote MTA supports 8-bit MIME transport?

I'm troubleshooting an intermittent issue where some international characters appear to be malformed after going through sendmail. I recently came across this article which describes the F=7 ...
0
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2answers
63 views

How to fix 'Relay Access Denied'

I'm trying to setup postfix as MTA on a AWS EC2 instance. I want to use this as mailserver for my domains and want to use it along with Outlook/Thunderbird. I've never setup postfix before, therefore ...
0
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1answer
48 views

Postfix use outgoing IP based on incoming IP used

I am using Digital Ocean's Floating IPs on my mail server. So I have two publicly available IPs that the server can use, and I would like to use whichever IP was used to reach the Postfix server as ...
0
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1answer
47 views

Configure sendmail to relay on an smtp server

I'm using an ubuntu distribution. And I installed the sendmail with apt, and edited the /etc/mail/sendmail.mc, and added the lines define(`SMART_HOST', `ssl0.ovh.net') FEATURE(`authinfo') before ...
1
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1answer
95 views

Using Amazon SES to send mails to specific domains in Zimbra

We are managing a Zimbra mail server Community edition. Since the IP Address reputation of our ISP is a bit poor, select domains (mail servers) are either blocking our emails which is resulting in ...
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0answers
44 views

MessageLabs Blocking Email but Not Our Provider

My coworker and I am at a loss here. MessageLabs is blacking our client's emails from sending. However, MessageLabs isn't our anti-spam provider anymore. I checked SonicWALL to see if they're still ...
0
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1answer
63 views

Spam sent from my dedicated server Centos/Postfix, no idea on how to block people from connecting

I've been reading a lot of topics here for the last 2 hours, made some change and yet I'm not sure how things happened and if things are fixed. First, this morning, I received an email from OVH, ...
1
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1answer
27 views

SPF redirect modifier

The SPF record for domain replace the current record. The macro-expanded domain is also substituted for the current-domain in those look-ups. Examples: In the following example, the ...
0
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2answers
45 views

Postfix Catchall - Avoid Spam

I've 2 accounts on my CentOS server configured with catchall email accounts. Lately I've been receiving bounced emails with virus that were supposedly sent from my server account, Ex: somestragename@...
0
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0answers
24 views

Sendmail not forwarding mail for domains in /etc/mail/local-domain-hosts

First off, I have been using sendmail for about a week, and have a semi-working instance. This issue very well may be something simple/overlooked. I have an AMI server that is running sendmail and ...