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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Postfix rejects SASL auth when dovecot is down

We're using Postfix with Dovecot and SASL Auth via Dovecot (based on this tutorial). All works like expected. But when Dovecot is down (i.e. for maintenance or other reasons) then clients could not ...
2
votes
1answer
474 views

Nginx Ubuntu Postfix Config - Can't connect to incoming IMAP server 'server not responding' but can send mail via outgoing using same details?

I'm pretty to new server admin and especially nginx but seem to be getting ok fine apart from accessing my mail via my iPhone? I've changed my domain to 'domain.com' The thing is I can send mail ...
2
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2answers
593 views

Send email through local SMTP vs google app engine

My web site is supposed to send email to customers and its hosted on a VPS. Should I use local SMTP or is it better to use a third party SMTP provider like Google App Engine? What are the ...
2
votes
1answer
2k views

how can i disable outbound mail in postfix?

i want to be able to send mail to someuser@localhost but not allow any mail to go out to the outside world from anyone to anyone. i've seen multiple entries about how to filter or restrict outgoing ...
2
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2answers
104 views

Does a receiving mail server (the ultimate destination) see emails delivered directly to it vs. to an external relay which then forwards them to it?

Let's say my users have accounts on some mail server mail.example.com. I currently have my mx record set to mail.example.com and all is good. Now let's say I want to have mails initially delivered ...
2
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3answers
258 views

proxy software to relay email

My some software applications need to relay emails to my email account. The only way they can do it via connecting to localhost which relays mail on behalf of application. I have forgotten the name ...
2
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5answers
749 views

Failed PCI Compliance - The remote SMTP server is vulnerable to a buffer overflow

Hey guys, I have tried allowing the scanners IP to be accepted through IPTABLES into the SMTP port, but the scan still fails. This is the error: The remote SMTP server is vulnerable to a buffer ...
2
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4answers
869 views

SMTP Port Redirection

As you know most ISP's block port 25 on outgoing mail. Some of my clients wish to use our mail server as an outgoing mail server. However, we do not have TLS or SSL. Is there a way to accept incoming ...
2
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2answers
5k views

How to configure Postfix to send bulk email at a “reasonable” rate per scond

Maybe a postfix newbie question. Our linux server is properly set up with an SPF record, and we don't send mass email at the moment. But, is there a simple way to configure the postfix mail queue, ...
2
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4answers
3k views

Postfix - sending emails to external domains?

I want to redirect my system mail to my gmail account, and I've setup postfix on an ubuntu server in an attempt to do so. However, when I telnet to 25 and send emails, the emails just appear to queue, ...
2
votes
4answers
618 views

Why is my email coming from a different domain or IP?

I have the following configured: mail.firstdomain.com - 1.1.1.1 - This domain sends out a lot of email (our newsletter to clients), and thus I keep the two separated. mail.seconddomain.com - 2.2.2.2 ...
2
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1answer
64 views

How easy is it to sniff the SMTP port of webserver to capture mails

I've got a very basic question that I don't know the answer for. Our company owns a webserver that runs multiple websites and works as a mail server for these websites as well (e.g. to send contact ...
2
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1answer
2k views

Postfix - Host or domain not found

I just installed Postfix on my ubuntu, on a local network. On this network, I have an Exchange Server (using domain mail.example.com). I had a problem sending an email to a local address : ...
2
votes
2answers
74 views

Postfix doesn't require authentication for local emails?

I've got a Postfix/Courier mail server (Authenticated with SASL/MySQL) all according to this tutorial. I'm currently running my server on Debian 6, it is a VPS. It works well as far as I can see but I ...
2
votes
1answer
3k views

Google SMTP Error: 454 4.7.0 Too many login attempts, please try again later

I discovered that while it was possible to use Gmail/Google Apps as an SMTP server for scripted use, if too many emails were sent I started getting error messages: SMTP Error: 454 4.7.0 Too many ...
2
votes
1answer
97 views

Simple, forwarding-only MTA?

I have a domain and a server. I’d like to have some e-mail addresses on the domain and I’d like to forward them elsewhere. I’d love to avoid running a full-featured MTA on the server, since they’re ...
2
votes
2answers
276 views

How to use postfix to carbon copy HP ePrint [closed]

I'd like to print using ePrint using a local e-mail (or alias) like printer@example.com instead of myprinter@hpeprint.com. For what I've already played with the ePrint service from HP, the service ...
2
votes
1answer
347 views

Opportunistic TLS for incoming mail with masked SMTP banner

I have a mailserver with opportunistic TLS enabled (Postfix smtpd_tls_security_level = may), however the SMTP banner is being masked by SMTP fixup on our FWSM. Before I disable this masking, is the ...
2
votes
1answer
496 views

Does snmpd support SNMP monitoring of SendMail queues?

CentOS 5.7 | SendMail 8.14.x I've got a CentOS box running snmpd and I'd like to monitor sendmail queues. Is this natively supported by snmpd or will I need to do something special to monitor it?
2
votes
1answer
611 views

2 Received from header at IIS SMTP email send via C# application

I am using windows server 2008 r2 and IIS 7.5 normally. I am using IIS 6 smpt server to send emails. Right now when i send email via my C# application i am seeing 2 received from headers. What might ...
2
votes
2answers
2k views

Postfix: Allow unauthenticated incoming mail, but only authenticated outgoing mail?

I'm new to the world of mail server's and have been working on setting up my own via Postfix on Ubuntu 11.10. So far, I have SASL authentication working over TLS so that's good; I'm worrying about ...
2
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4answers
2k views

Google SMTP Connection Timeout

How do I find out why Gmail is seemingly refusing connections from my specific IP range? I'm getting a "Connection timeout" error when attempting to send email through smtp.gmail.com using the email ...
2
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2answers
2k views

Does Exchange 2010 impose a maximum length for individual headers? If so, what is it?

Does Exchange 2010 impose a maximum length for individual headers? If so, what is it? Let's say a user sends an email to 200 recipients, resulting in a TO: field having 200 email addresses (very bad ...
2
votes
1answer
78 views

Rejecting bad attachments best practice?

When configuring a mail server, what is the best practice for rejecting an inbound internet email with an executable type I'd like to disallow? Easiest option is an NDR/DSN, but I'd think that could ...
2
votes
1answer
1k views

Test SMTP security with OpenSSL?

I'm getting ready to deploy a new SMTP server, and I'm not sure how to ensure that it is using strong encryption. The server software is Postfix running only SMTP. I've added the following to the ...
2
votes
1answer
130 views

Effect of adding an external SMTP to a mailbox

For an Exchange mailbox (specifically 2007) an e-mail address can be added to the "E-Mail Addresses" tab of a user account. What is the effect of adding an external email? for instance, the user's ...
2
votes
3answers
877 views

Why doesn't Postfix announce AUTH during EHLO?

I have setup postfix and dovecot, I can even receive e-mails and pick them up remotely using Thunderbird client connecting via IMAP However, I can not send out using the Smtp server, when I telnet ...
2
votes
2answers
220 views

Ubuntu, mail servers and MX records

Some background: I have set up an Ubuntu cloud server on Rackspace where I host two domains, say, www.domain1.co.uk and www.domain2.co.uk. Both domains are hosted on the same cloud server. I ...
2
votes
1answer
133 views

Sending email from specific vhost, bad for spam?

Essentially, I have a server that contains many vhosts. One vhost in particular is required to send mail from the address invitations@vhost.com, however the reverse DNS for that server resolves to ...
2
votes
2answers
124 views

E-Mail blocked because of IPs in Trace-Fields (“Received”)

we have an SMTP problem. Our setup is a internal Exchange server and an external mail gateway (exim) with a DNS entry and MX record. This gateway accepts all mail for our domain and accepts relaying ...
2
votes
2answers
5k views

How to setup a Postfix SMTP-only for multiple domains

This is my first question on Stacks. I always read a lot of solutions to problems here almost every other day. So thank you to all contributors. I am a noob here so please spare some space if I am ...
2
votes
3answers
197 views

setting up an email server

i'm about to stop using gmail apps premium and i'm looking at using hmailserver and either zimbra or roundcube as the front end. My question is this: does hmailserver fit well with zimbra or ...
2
votes
1answer
131 views

Looking for a simple free smtp server [closed]

I have a client looking for a decent free mail server for Windows 2k2 R2. They are looking at sending mail mostly but if receiving is possible that is a plus. I know that Windows comes with smtp but I ...
2
votes
2answers
443 views

How to change default sendmail SMTP error codes, responses, and/or DSN text?

CentOS 5.x - SendMail Hi Guys, I'm curious -- is there any way to customize the STMP error codes, response text, and/or DSN body text in sendmail? If so, where is this stored? Thanks, Mike
2
votes
2answers
1k views

IIS6 cdo.message cannot send emails access denied error

Got some very basic email code on a iis 6 server to send a test email. Relay is enabled on exchange server for this server, the iis user has write permissions to the directories for mailroot and all ...
2
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3answers
3k views

Exchange 2003 SMTP Error - 'Is Restricted'

We're getting the following Error when emailing a client. There was a SMTP communication problem with the recipient's email server. Please contact your system administrator. ...
2
votes
3answers
496 views

SMTP throttling

I need to be able to restrict the amount of bandwidth used by SMTP port 25. Basically, we have a routine in our server software that will send out bulk faxes, not much data per fax but a lot of ...
2
votes
1answer
49 views

How can I enforce TLS in sendmail when I don't necessarily know the hostname of the downstream MTA (only IPs)? [e.g. by recipients' domain]

I'm running SendMail 8.14 and have some custom static routes for sending to certain domains. These domains are "internal" but not managed directly by me. Here's an example of ...
2
votes
1answer
45 views

Service Closing transmission on OpenSSL [duplicate]

I am trying to send email through OpenSSL as below : Client > openssl s_client -crlf -connect smtp.mail.yahoo.com:465 SERVER > 220 smtp.mail.yahoo.com ESMTP ready Client > HELO localhost ...
2
votes
1answer
121 views

Unable to Connect to SMTP Host

I am trying to configure Postfix on CentOS 6 server, and the problem is that I cannot receive mails. I tested it on http://mxtoolbox.com/ and I get an error Unable to Connect to SMTP Host. I check ...
2
votes
1answer
77 views

Exim retry is Message based instead of host based? why

from what I understand exim retries are supposed to be HOST based, NOT message based. This seems to make sense to me; if a host's server is overloaded or otherwise telling you to "delay sending ...
2
votes
1answer
360 views

Exchange Server 2010 Relaying Spam

Recently I began receiving AOL spam feedback reports from our exchange server. As I investigated I found that hundreds of spam messages were being relayed through our exchange server. Although I am ...
2
votes
2answers
170 views

My Email Server is rejecting incoming mail

I've got a Windows 2008 Web Server and have just installed Smartermail Mail Server Software. The server will send messages but the replies bounce back. I have attached my dns entries Ports 25 and ...
2
votes
1answer
525 views

Exchange 2010 - can't send to a specific domain - 421 connection dropped due to socket error

I've looked at a few of the existing SF questions/answers and so far can't find the same situation. It's not a TLS issue like I first thought, since the remote server isn't asking for TLS, and it ...
2
votes
1answer
1k views

Zimbra ZCS 7.2.1 MTA Deferring e-mail

Zimbra 7.1.2 and the MTA seems to be deferring e-mail when it is received. Oct 1 09:35:42 www postfix/error[16614]: 5FB8C1A803EE: to=<xxx@xxx.xx>, relay=none, delay=0.15, ...
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1answer
1k views

How the Postmaster@domain address works

I'm very new to Exchange (in fact, an apprentice and studying it at the moment) and am wondering how the Postmaster@domain.com address works. An example: A smarthost configured with one mailbox, ...
2
votes
2answers
1k views

IIS/SMTP - unable to move emails from inetpub/mailroot/Queue due to file lock

I have a listener that processes emails in the inetpub/mailroot/Queue directory. Once the listener is done processing an email it proceeds to move the email to another directory. However, moving the ...
2
votes
2answers
1k views

mail server: retry timeout issues to and from specific domain

we have a dv server with mediatmeple, running apache 2.2, and plesk panel 10.3. for some reason, when sending mail from our domain to theirs, or when they send email to ours, the messages bounce back ...
2
votes
1answer
389 views

Example smtp dsn bounce messages for testing

I'm working on building a feature for a larger system that will be able to parse and react to dsn bounce messages received from all different types of smtp servers. It be great to test the code I ...
2
votes
1answer
218 views

How do I configure my domain and web application so the emails send from the latter are not blocked as spam?

I have a WordPress site that needs to send notifications to an email address. I would like the from field from this emails to be an address on my client's domain. I dont know much about email ...