Questions tagged [smtp]

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.

5
votes
1answer
1k views

Is null return path reliable indication of a bounce?

I have a mailbox that receives bounces as well as normal email (the latter includes messages from automated services). I want to filter out the bounces and forward them to another mailbox. Assume I ...
5
votes
4answers
7k 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 ...
5
votes
1answer
7k views

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

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 ...
5
votes
2answers
21k views

554 5.7.1 <mail_addr>: Relay access denied centos postfix

I have problem in send mail from postfix in centos I have following setup mail server postfix for sending mail but I am getting error. As in the link I tried following commands telnet localhost ...
5
votes
2answers
7k views

Can't connect to SMTP server

I have trouble connecting to an SMTP server from my PC. I use Debian sid. telnet mail.example.com 25 Trying 12.23.34.45... telnet: Unable to connect to remote host: Connection timed out While from ...
5
votes
2answers
2k views

Simple SMTP server which can redirect all mail to single address?

We're in the process of setting up a continuous-integration server (Hudson running on CentOS5), and some of our unit tests will cause email to be sent. We'd like to configure the server so that all ...
5
votes
5answers
2k views

Dummy SMTP server as a service

I have a Windows Server 2008 machine with IIS installed which is hosting a webapp that is sending some notification mails once-in-a-while. What I'd like to do is to monitor the email sent by the ...
5
votes
1answer
248 views

Is Exchange 2010 compliant with RFC 3848

I have looked up Exchange 2010 Support for RFC Standards but do not see RFC 3848 amongst the supported standards. I do see RFC 4954 listed, which 'recommends use of RFC 3848 transmission types', ...
5
votes
1answer
1k views

saslauthd multi instance for postfix smtp authentication

I have mail server Postfix+Saslauth. I configure multiple instance for Postfix: postfix postfix-out and two instances for saslauth: saslauthd saslauthd-out Setting saslauthd is for ...
5
votes
1answer
4k views

IIS SMTP TLS encryption issue

I enabled TLS in IIS SMTP Virtual Server with a self-signed server certificate. Made sure that the certificate has the FQDN of the server. Checked the TLS encryption checkbox in Virtual SMTP > ...
5
votes
2answers
2k views

Configuring Monit to Send Mail through Office365

I'm trying to configure monit to send emails through Office365. Here's the relevant configuration: set mailserver smtp.office365.com port 587 username "username" password "password" using ...
4
votes
3answers
20k views

Does MX Records have anything to do with outbound email?

I'm really confused about the MX Records and generally with email. I've set up Haraka SMTP server for outbound email delivery because I need to send sign up validation emails. If I don't want to ...
4
votes
6answers
690 views

receiving mail during Exchange maintenance?

I was part of a small company, and sometimes we had to bring down our Exchange server to perform maintenance. The majority of mail during the downtime would get redelivered in a timely manner, but ...
4
votes
3answers
14k views

POSTFIX main.cf permission denied

I am trying to set up a postfix server for smtp relay. Centos 5.5 I have followed http://mhawthorne.net/posts/postfix-configuring-gmail-as-relay.html but am getting a FAILED error when trying to ...
4
votes
2answers
147 views

In SMTP, how does one choose between “Accept than Bounce” vs “Bounce at the edge”?

There seems to be a variety of implementations of SMTP that either immediately reject a message, and others that do an accept, then bounce the message. Operationally, the accept-than-bounce is a ...
4
votes
5answers
654 views

Why is my port 25 so active?

Using netstat -na I notice that I have a lot of connections like tcp 0 0 XXX.XXX.XXX.XXX:25 YYY.YYY.YYY.YYY:13933 ESTABLISHED tcp 0 0 XXX.XXX.XXX.XXX:25 ZZZ....
4
votes
3answers
5k views

SMTP sent E-mail not copied to Sent Folder [closed]

I discovered that some (few) providers don't copy into the Sent folder those E-mails which are sent from mail clients through SMTP. They only copy them to the sent folder if you send them from their ...
4
votes
2answers
2k views

How to copy outgoing messages on sendmail

I've searched the serverfault and Google, but did not find anything related to my question yet. So, I have a customer that wants to read all emails sent by his employees. I've configured a VPS with ...
4
votes
2answers
103 views

Spam addressed to a sender but received by everyone else

Spam's been getting through Postini lately that's addressed to a recipient (bob@example.com) in the To: field and in the headers. While this isn't that strange -- we've had spam get through before -- ...
4
votes
5answers
40k views

How do I configure reverse DNS for a SMTP server [duplicate]

We use iis 6 to send out emails for our website but some email addresses bouce backs. It only appears to be 2 addresses. There is at least 100 different email addresses sent to at the same time as ...
4
votes
3answers
2k views

Logwatch is not respecting MailFrom

I've gone through today to setup Logwatch on my server and have installed this all successfully. I've followed this guide on Digital Ocean and set the MailFrom parameter to: MailFrom = mailer@...
4
votes
2answers
1k views

Postfix protocol error attempting email address validation with SMTP

I have some code that does an email address validation. It works by attempting a mail delivery via SMTP and then quitting without sending anything. It works most of the time, but in some fringe cases ...
4
votes
2answers
669 views

When DKIM is installed, will I still be able to send email for my domain from gmail?

Let's say I own example.com, that I install and configure dkim on my server (apt-get install opendkim opendkim-tools, etc.), and that I add the relevant public key to the domain's DNS records. Then ...
4
votes
1answer
566 views

Need help determining origin of spam email

As a quick background we have spam that is being sent out with our domain name. As a result we have added SPF record to our domain DNS, now obviously this will assist in making sure this spam is not ...
4
votes
1answer
9k 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 ...
4
votes
1answer
450 views

Postfix SMTP authenticated can send as anyone

The server correctly accepts/rejects the logins though dovecot's authentication mechanism, but after that I can pretend to be anyone when sending emails. smtpd_sender_login_maps = texthash:/etc/...
4
votes
4answers
5k views

How do I get a SMTP session log in Exim?

Sometimes when debugging SMTP issues the standard maillog is not enough and I need to see the full SMTP session. In postfix I add the problematic IP to "debug_peer_list" which will enable the session ...
4
votes
1answer
16k views

Question on SendMail daemon actions when load average is too high

My sendmail server started rejecting connections because load average was too high (due to a spam issue that has since been resolved). Error was: sendmail[13400]: rejecting connections on daemon MTA:...
4
votes
1answer
32k views

Postfix NOQUEUE: reject: RCPT from unknown

I built a web based application but when it is trying to send an e-mail it fails. Postfix logs the following in it's mail.log: postfix/smtpd[22261]: warning: hostname srv.eastinc.nl does not ...
4
votes
3answers
2k views

Foreign mail server returns “502 Command not implemented.”

I am using Postfix to communicate with foreign server and send a mail. Every time when I try send mail using Postfix, I get this error: (host mx2.seznam.cz[77.75.76.32] said: 451 Local Error (in ...
4
votes
2answers
1k views

Postfix SMTP Relay Configuration Error

For the last day I was searching for solutions for this problem: My postfix(+dovecot) configuration is fully able to receive e-mails and to serve them via IMAP but it fails at accepting them via SMTP ...
4
votes
2answers
8k views

Rate limit exim per user basis

How can I implement "rate limit" in Exim so that every user in my exim can send specific number of emails per day. List A of Users can send 100 emails per day and the list B of users can send 500 ...
4
votes
2answers
14k views

How do I track whether a email was successful among thousands (IIS 6, .NET 3.5)

I want to be able to tell if an email sent to a user is successful or not. I've tried looking at the SMTP logs and there appears to be no way to link server requests with server responses. So if I ...
4
votes
2answers
19k views

Postfix What does “Queued mail for delivery” mean?

I sent an email to 2 receipients and I checked maillog: tail -5000 maillog | grep "020EE4202065" Aug 7 17:31:24 mail postfix/smtpd[7478]: 020EE4202065: client=NodoOffice[118.70.28.223], sasl_method=...
4
votes
4answers
20k views

SMTP Server 550 Access denied - Invalid HELO name

A bank we're working together is trying to send us an auto generated email to our company's email but it keeps bouncing off with the following SMPT error: Status: 5.5.0 Diagnostic-Code: smtp;550 ...
4
votes
5answers
24k views

SMTP Reverse DNS Mismatch

My dedicated server ns382087.ovh.net resolves to 46.105.98.72 and hosts multiple domain with several dedicated IP addresses. Each new IP address is added to /etc/network/interfaces Among them, the ...
4
votes
6answers
11k views

How to send Bulk email with SMTP server

How do email marketers get success while sending mails? Though their emails volume is very high, they can deliver mails with out any problem like spam or bounce. If we try to send bulk mails with our ...
4
votes
2answers
14k views

How to remove the SMTP address for a secondary domain from all Exchange mailboxes?

I have an Exchange server which used to manage multiple SMTP domains; now it only has to manage one. I have already removed the secondary domain from all address policies; I need to remove all SMTP ...
4
votes
1answer
5k views

Log with iptables which user is delivering email to port 25

Because we got blacklisted on CBL I set up the following firewall rules with iptables: #!/bin/bash iptables -A OUTPUT -d 127.0.0.1 -p tcp -m tcp --dport 25 -j ACCEPT iptables -A OUTPUT -p tcp -m tcp -...
4
votes
2answers
4k 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
6answers
3k views

What is causing email sent from my Google Apps account to bounce?

I have started to get Delivery Status Notification (Failure) messages in response to emails sent from my Google Apps domain account (at offby1.net): Delivery to the following recipient failed ...
4
votes
2answers
5k views

Postfix dynamic smtp_helo_name

I have a mail server that relays e-mails for two different domains. I want the smtp_helo_name to be different based on the domain. I'm assuming there is no way to do this via checking the mail headers,...
4
votes
2answers
2k views

SMTP defer vs reject

When should I use defer and when reject? In my case there is postfix running. The parameter smtpd_relay_restrictions defaults to defer_unauth_destination, while the Access Readme suggests ...
4
votes
1answer
3k views

Do any versions of Microsoft Exchange Server support RFC 5336 / 6531(Internationalized mailbox names)?

https://en.wikipedia.org/wiki/Extended_SMTP#SMTPUTF8 The SMTPUTF8 extension allows UTF-8 encoding in mailbox names and header fields. This provides the capability for sending email to ...
4
votes
1answer
2k views

Sendmail: “TLS verify=FAIL”, “554 5.1.8 : Sender address rejected: MX record not found”

Have been struggling for a day already and can't find solution. When try to send mails to some hosts: Jan 5 10:31:37 vps**** sm-mta[2192]: STARTTLS=client, relay=mail-x.*****.co.uk., version=TLSv1/...
4
votes
1answer
5k views

How to setup postfix to check SPF record only for domains that i want to check

I have working postfix server. It configured with amavis and uses pretty good SMTP headers control. But sometimes my users receive spam from spammers with well known mail service providers addresses. ...
4
votes
2answers
4k views

Postfix & Amavis - Use UNIX Soket for Communication

I currently using a complex mailserver setup using Postfix, Dovecot, Amavis and Spamassassin. Everything works fine but I want to improve the Postfix-Amavis-Communication. At the moment, postfix will ...
4
votes
2answers
7k views

How to stop or prevent Postfix / smtpd / Sasl brute forcing

There are numerous attempts to connect to my mail server in order to send mail either unauthenticated or to guess username and password to, I suppose, accomplish the same. Should I fight against that,...
4
votes
2answers
3k views

Timeout error in all my apps for every call to smtp servers

On my VPS (a tophost.it "TopServer" with Ubuntu 12.04 LTS), since a few days ago all my apps are became unable to send emails. All I could learn from the logs is that every request goes timeout. I ...
4
votes
1answer
2k views

postfix misconfigured: “mail for (domain) loops back to myself”

I've just installed postfix on my debian system, so I have a default configuration, apart from the following values in /etc/postfix/main.cf: myhostname = mydomain.com alias_maps = hash:/etc/aliases ...