I am having issues with SMTP from one of my web servers. I've verified firewall connectivity over port25 to the SMTP relay and the exchange servers is good to go. I can hit the SMTP relays and exchange server from my web server via telnet. Whenever I drop a mail in Pickup it sits in the queue.
In Event Viewer I get:
Message delivery to the host 'IPADDDRESS' failed while delivering to the remote domain 'MYDOMAIN' for the following reason: The connection was dropped by the remote host.
I checked SMTPDiag and it comes back:
Error: Expecting "220". Server is not accepting connections.
Failed to submit mail to "server.domain.com"
I checked and my connection control is set to allow and the domains are listed in SMTP.. I am losing my mind trying to figure out why mail is failing at this point..
Are you hitting a rate limit or is your outbound ip on a blacklist? Try the blacklist search here: https://mxtoolbox.com/supertoolmobile.aspx
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I'm trying to configure hMailServer on my computer to be able to send email out and also receive emails. I'm not sure if I have everything set up correctly as some tests works and some others do not so I am confused.
I have already set up in the DNS of my domain these 3 MX records:
mail.example.com
smtp.example.com
imap.example.com
Each one of those records points to the domain name of my server. I am able to connect to the web server of my domain. In my router, I have forwarded ports 25, 110, 143, 465 and 587 to my local computer running the hMailServer application. When running a port check on the web, it looks like port 25, 110 and 465 are blocked, but the rest are not.
If I open my Mozilla Thunderbird mail client, I set up an account I created in hMailServer for the domain in question.
I have also allowed the hMailServer application through my Windows firewall for both the private and public networks. I did the same for the Thunderbird email client.
I can locally send emails to myself and other local domains set up in hMailServer. However, I cannot send or receive any email to/from external recipients, like to/from Gmail or Hotmail for example. I'm getting this error message:
Error Type: SMTP
Connection to recipients server failed.
Error: Host name: 1.1.1.1 (edited) message: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond
Here are the TCP/IP ports summary in hMailServer:
The second part of my question is once I can actually send and receive email to/from external domains, how would I secure the connection (SSL/TSL...)? I already have a SSL certificate for my web server (example.com and www.example.com). Do I just need to generate another one for say mail.example.com or do email servers use a different kind of certificate?
I'm trying to configure the outbound mail service on alfresco behind a firewall, I add the mail configuration on alfresco-global.properties but it can connect to the remote smtp server, there's a connection timed out error in the log. I guess I need to open the correct port but which one?
I'm trying to send an email to my IIS (6) SMTP service.
The domain mycustomer.myserver.comis added to the domains list of the SMTP service. Port 25 is open, I can telnet there.
telnet mycustomer.myserver.com 25, gives no errors, but no message either. (other mail servers do show 220).
SMTPDIAG confirms this: Error: Expected "220". Server is not accepting connections.
Failed to submit mail to mycustomer.myserver.com.
Do I need any further configuration of my IIS SMTP to get this to work?
At this point, I do not have MX records, but I don't think that is the problem?
OK found it:
Allowed connections were restricted to localhost, as configured under Access > Connection control.
Do the SMTP logs on a server (Windows 2003) only show logs of mail that were sent successfully?
We are getting bounce backs when sending mail to a particular domain:
The connection was dropped by the remote host.
It looks like a problem on the receiving server, but we dont have much information to provide them. We can send to hotmail, gmail, yahoo etc OK.
Any ideas?
Most likely, there is a spam filter in front of the receiving mail server for this domain, and this spam filter thinks your mail server is sending spam, so it's closing the connection from your mail server. One way to test this is to simulate sending a message to this mail server by opening a command prompt on your mail server, and use telnet to connect to the receiving mail server on port 25, and proceed with the process of sending a message just as a mail server would. This way, you'll be able to see how the receiving mail server responds after each step. Follow the instructions in http://support.microsoft.com/kb/153119 to see how this is done.
It turned out the sending server was blacklisted by McAfee, that was running on the receiving servers firewall.
For those that may have the problem in the future you can check if your server is blacklisted with McAfee here:
http://www.mcafee.com/threat-intelligence/ip/spam-senders.aspx
After entering your server IP, you should see a link Threat Feedback. Use this to email McAfee.
I was able to send McAfee an email with an explanation, they then removed our server from the blacklist.
I would like like guidance regarding an issue we are having on our CentOS server.
Just recently we noticed that we cannot send emails to Hotmail.com mailboxes from our domain email. I also discovered that we're getting a lot of mail delivery failure emails in one of the inbox's that we don't use.
I've checked the mail logs and saw some suspicious activity. Unfortunately, I don't know much with regards to mail server and how they behave. Can someone shine some light on this situation and tell me if some is connecting to our SMTP server remotely and sending spam emails to various recipients? What other steps should I take to prevent this?
Here is part of the log:
2013-06-09 05:43:27 SMTP connection from [110.52.1.237]:13088 (TCP/IP connection count = 1)
2013-06-09 05:43:32 no host name found for IP address 110.52.1.237
2013-06-09 05:43:41 SMTP connection from [110.52.1.237]:13461 (TCP/IP connection count = 2)
2013-06-09 05:43:46 no host name found for IP address 110.52.1.237
2013-06-09 05:43:46 unexpected disconnection while reading SMTP command from (iem.net) [110.52.1.237]:13088
2013-06-09 05:43:55 H=(qbnngj.com) [110.52.1.237]:13461 sender verify fail for <wqnsjzyyc#qbnngj.com>: The mail server could not deliver mail to wqnsjzyyc#qbnngj.com. The account or domain may not exist, they may be blacklisted, or missing the proper dns entries.
2013-06-09 05:43:55 H=(qbnngj.com) [110.52.1.237]:13461 F=<wqnsjzyyc#qbnngj.com> rejected RCPT <support#greenXXXX.com>: Sender verify failed
2013-06-09 05:43:55 unexpected disconnection while reading SMTP command from (qbnngj.com) [110.52.1.237]:13461
As you can see above, the IP that connected to the SMTP server is from China. I have a dozen of similar connections made in the log.
I am not sure how to resolve this issue.
Any help would be appreciated.
Thank you,
Max
You have two separate problems.
Sending to Hotmail: They have a web page regarding their own private white list, and if you're not on the list, you get blocked.
Receiving delivery status notices for messages not sent: Someone is spoofing your domain in messages they're sending to others. You need to protect your domain with some authentication technology. The two most common are called "sender policy framework" and domainkeys.