Simple Mail Transfer Protocol (SMTP) relaying (transferring between computers).

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17
votes
5answers
142k views

How to correct Postfix' 'Relay Access Denied'?

This morning, in order to correct a problem with a name mismatch in the security certificate, I followed the recommended steps from How to fix mail server SSL?, but now, when attempting to send an ...
7
votes
1answer
3k views

How can I configure Postfix to ignore relayhost for some domains?

Is there a way in Postfix to ignore the relayhost? I have something like relayhost = [smtp.domain.net]:587 Now for a certain domain I don't want to send it out to that relay but want it to just ...
6
votes
1answer
22k views

How to configure sendmail to send email via GMail (smtp.gmail.com), using port 465 or 587?

I have configures sendmail to send email via my GMail (Google Mail) account, i.e. via smtp.gmail.com, by editing /etc/mail/sendmail.mc and regenerating sendmail.cf: -dnl ...
4
votes
2answers
2k views

Sendmail on Ubuntu trying to use Google Apps servers as a relay, by default?

I have a recently installed Ubuntu (natty) server, with a domain pointed to it. The mail for this domain is handled by Google Apps (via MX dns records pointing to Google's mail servers). Now, I've ...
4
votes
3answers
83 views

How to limit amount of email sent by postfix to certain domains and control it by using mail header?

Goal I'm looking for a solution to limit rate of e-mails sent to specific e-mail operator (several Top-Level domains, all of them I know) on hourly basis. I also need some way to control the rate on ...
3
votes
2answers
19k views

Easiest way to configure local SMTP server to relay through gmail on Windows?

We have gmail for our corporate email provider. I want to be able to send mail through smtp.gmail.com from ASP.NET. I have managed to do this just fine - and it has the benefit of all sent items ...
3
votes
4answers
4k views

SMTP relay through GMail overrides “from:” address with “[me]@gmail.com”

I've been trying to figure out if this is a new "feature" or if there is an issue with my configuration. I'm using Ubuntu 10.04 Desktop with Postfix as MTA. My smtp (as opposed to smtpd) ...
3
votes
2answers
84 views

SMTP: Which IP should I monitor?

I use a relay server to deliver external mails. I use relay server's IP in SPF record. But I'm not sure about blacklist monitoring/checking. Should I check main server's IP or relay's IP?
3
votes
3answers
996 views

How to force Windows Server 2008 R2's SMTP server to generate NDRs for non-existing local users?

I have a Windows Server 2008 R2 server with the SMTP service enabled, which provides mail relay to another server for some applications. Sometimes, a message comes in with a wrong "To:" address, ...
3
votes
1answer
2k views

Preventing email blasts with Exchange 2010 IP Throttling (or any other technology)

We need to slow down the rate email spam is sent through the Exchange system from our developers' buggy applications. How can I throttle email messages in Exchange 2010 by Source IP, or sender, so ...
3
votes
2answers
365 views

Security Risk involved in disabling SMTP authentication on POP3 Server?

I provide IT Services to a client who, for the longest time in the world, has been using a POP3 server from Network Solutions to handle their email. At this time, I'm introducing the McAfee SaaS ...
3
votes
1answer
293 views

Creating a “fake” open relay to capture non-relayable outgoing mail with postfix

We occasionally have customer-provided servers in our technical support and engineering departments. They're isolated on their own VLAN, with strict firewall rules in place to minimize possible bad ...
3
votes
3answers
3k views

Sendmail relay out of Amazon EC2?

I have a site running on CentOS 5.4 through Amazon EC2. Unfortunately, Amazon has had nothing but trouble with their entire IP range getting black listed from spam tracking services regularly. I need ...
3
votes
1answer
250 views

What PID is making outbound connections on port 25?

What is the most ready way to log the PID and process name of anything making an outbound connection on port 25? This is on a 2008 x32 server without the windows firewall enabled. I'm ...
3
votes
0answers
645 views

Postfix sasl relay host - weird behaviour

Previously I had a relayhost set in postfix to mailhost.zen.co.uk - I don't think it accepts SASL - only TLS. So I though I would try changing to a different relay host. However, the following log ...
2
votes
2answers
191 views

Multi-site email relay based on email address (in AD?)

We have a multi site setup currently based around Exchange 2003, but we are getting a lot of traffic over the vpn as only one server has an internet facing IP. Is there such a product that could sit ...
2
votes
3answers
3k views

How to get Postfix to send/forward/relay to a sub-domain located on another server?

I have a quick question. How do I setup postfix to send an email to another server (Exchange Server) when sending to an email address that has a sub-domain of our main server. For example, say our ...
2
votes
2answers
555 views

Has this server been compromised?

A friend is running a VPS (CentOS) His business partner was the sysadmin but has left him high and dry to look after the system. So, I've been asked to help out in fixing an apparent spam problem. ...
2
votes
2answers
1k views

Postfix relay with Exchange Server

Is it possible (or even logical) to use Postfix as relay MTA with Microsoft Exchange Server 2007, and if so how?
2
votes
2answers
108 views

MTA handling of too large emails

If an MTA receives an email that exceeds the message size limit, which bevaviour is preferred? What is the default for common mail servers? Reject the email during the SMTP session. The delivering ...
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
votes
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
votes
2answers
455 views

Can I have Postfix relay for everyone on a second port?

I have a Postfix instance on an EC2 server which will need to accept mail from the outside world (e.g. port 25 will be mapped to it from a virtual IP.) I also want to use this server to send mail ...
2
votes
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
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
100 views

Upgraded Postfix, Relay Is Broken Now

I upgraded from Debian 5 to Debian 6, and in doing so went from Postfix 2.5.5 to 2.7.1. I'm using MySQL as a backend for virtual domains/mailboxes. After the upgrade, I'm able to receive mail from ...
2
votes
5answers
5k views

Virus sending phishing emails through exchange server

It appears that there is a virus on my network somewhere that is sending phishing emails through my exchange server. I can see the messages in message tracking and I see many SMTP errors for NDR's and ...
2
votes
1answer
639 views

Exchange 2010 OWA send connector issue

I have problems sending emails outside organization using OWA (Exchange 2010 installed on SBS 2010, domain is domain.local, local DNS). Web-server and email server are hosted remotely, I am using pop ...
2
votes
2answers
172 views

When is a mail relay needed?

Let me expand... I have a client who is unhappy with their current hosting situation. They want me to move their website and domain across to my hosting platform. I can do this. However I have ...
2
votes
1answer
2k views

Sendmail relaying denied despite successful authentication

I don't have a lot of experience with maintain a mail server, but in spite of that I must configure sendmail as a MTA for one of my servers. I have a problem where sendmail responds to the MUA that is ...
2
votes
2answers
375 views

Smtp relay service recommendation to increase deliverability [closed]

I need a recommendation for a email relay service to use on multiple domains with C#. I don't want to worry about blacklisting and am looking for increase deliverability on confirmation emails etc. ...
2
votes
3answers
2k views

Is It Possible To Configure Team Foundation Server With Smarsh Exchange?

Our company recently migrated to an externally hosted Exchange server provided by Smarsh. Is there any documentation on how to setup Team Foundation Server (TFS) 2008 and 2010 with an external ...
2
votes
1answer
178 views

postfix transport relay access denied

When message arrives from other mail server (yahoo/gmail) on my postfix server it gets denied and not being transported using the transport on my configuration. Been checking whole day can't find ...
2
votes
1answer
1k views

Postfix stop outgoing delivery but accept all incoming

I'm doing development for a webapp that sends emails out to users. I've typically used Argosoft Mail Server (Freeware) in a windows environment as an SMTP server in which I've enabled relay but ...
2
votes
1answer
114 views

Postfix as a relay for specific networks only

I have a strange issue with postfix that is driving me a little up the wall as it seems to work 50% of the time but with no changes made. What I want to achieve: I have a number of virtual servers ...
2
votes
1answer
180 views

SBS/Exchange 2003 Open Relay on Malformed Email Address

I have a Small Business Server 2003 (Exchange 2003 SP2). During a PCI Compliance audit, it was flagged as failing the open relay. I've used telnet to test, and here is what I've found: MAIL FROM: ...
2
votes
1answer
612 views

IIS SMTP Relay to Google Apps adds header to e-mail body

I have an IIS6 SMTP set up to relay e-mail for applications on my intranet that does not support TLS to a Google Apps e-mail account per this tutorial. For the most part it is working great, but when ...
2
votes
1answer
933 views

Postfix sasl relay host - failure

I'm trying to set up SASL to a relayhost to send external email. I've read a hell of a lot and done everything I'm supposed to have done. However our provider won't accept me relaying emails with (we ...
2
votes
1answer
2k views

How do I configure MailEnable on Win 2k3 to allow Google to relay SMTP through it?

We use "Google Apps for Your Domain" for email, but wish to use our old email server for sending mail. The reason being that Google Apps SMTP is blacklisted by several of our partners as being ...
2
votes
1answer
57 views

Postfix multiple checks

I want to achieve the following with Postfix: Run all emails through a black list Allow any clients sending to a list of domains Allow some clients sending to any domain This is what I have: ...
2
votes
1answer
80 views

5.7.1 SMTP error when running stored proc using DB Mail in SQL Server 2012

I am getting an error in SQL Server 2012 Database Mail when executing a stored proc to send an email from a specified address to a specified address using Office 365 as the SMTP server. The mail ...
2
votes
1answer
53 views

SMTP routing cases: same @domain as sender and different @domain

I would like to know what is the difference between sending an email to the same @domain as the sender and sending to a different domain. I cant really find a detailed explanation on the web. From ...
2
votes
1answer
172 views

What's wrong here? Postfix secondary MX relay with redirection of specific email addresses

The primary mx server for my domain is down, and is likely to be down for a day or so. Meanwhile pressure is on to get sme high priority mail to people who need it. What I want to do is set up a ...
2
votes
0answers
178 views

How to identify the user/computer that is relaying spam through a mail server?

For the past couple of days, at certain intervals, a huge load of email is dumped on my Exchange 2003 server and relayed out until it gets blacklisted everywhere. Nothing like this happened for many ...
2
votes
1answer
243 views

SMTP Event Sinks in Windows 2008 R2

We use a 3rd party software to send Bulk Emails. The software does not provide options to add Email addresses in BCC. However, as per Compliance Rules, it is necessary for us to add a BCC address to ...
2
votes
2answers
5k views

Exchange Connector Won't Send to External Domains

I'm a developer trying to get my .Net application to send emails out through our Exchange server. I'm not an Exchange expert so I'll qualify that up front!! We've set up a receive Connector in ...
2
votes
0answers
29 views

I need to set-up the blocked machine to relay to the unblocked machine using a different port

I have two Windows Server 2003 machines sitting in a network. Server B has port 25 open and can relay emails to the local network's smtp server. Server A does not have port 25 open. How can I set it ...
2
votes
3answers
2k views

Ubuntu Postfix Gmail SMTP Relay Not Working

I currently have postfix set up to relay messages from my websites through gmail, and up until recently it was working perfectly. However, within the last week or so (not really sure when) I started ...
2
votes
4answers
1k views

Send emails from Linux via Google SMTP

I've gone as far as I can go on my own, but I'm not a Linux guru and am now stuck. I've got an Oracle database running Oracle Enterprise Linux 5.1 on an Amazon EC2 instance. I migrated it from a box ...