RoadRunner rejects SmarterMail. Too many concurrent connections.
Problem reported by Ronald Raley - April 1, 2016 at 5:07 PM
Submitted
I need some help with this one.  Suddenly, Roadrunner (rr.com) is rejecting our e-mails.  See below:
 
Reason: Remote host said: 421 4.7.1 - Connection refused - <x.x.x.x> - Too many concurrent connections ( <4> ) from source IP
 
I tried reducing Max Delivery Threads from 100 down to 50.  This did not fix the issue.
 
I have tried to white list our organization with this Time Warner owned company, but they will not because the e-mails we send are "user-generated."  What difference does that make?  Only if we pay them some $$$ can we be white listed.  These big companies think they are so secure and safe, yet they kill productivity.
 
So my questions are:
 
How can I throttle outgoing mail from one particular user account?
If that is not possible, can I set SmarterMail to connect to this particular server one message at a time?
 
Any help is greatly appreciated,
Ron

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Paul Blank Replied
Perhaps you have some kind of mail server server hijack going on. If you haven't carefully checked for that...
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Ronald Raley Replied
I have reviewed the logs and do not see any type of hijacking.
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CLEBER SAAD Replied
The problem it's not with your SM. Try to talk with the destionation Administrator or see the postmaster policy. Some service provider don't allow more than 5 connections per IP / minute. If it's occurs the sender IP become blocked for 1 hour.

-> http://postmaster.rr.com/
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Ronald Raley Replied
Thank you for your help. I will contact them to get the exact requirements.

But unfortunately, I don't see a clear method to limit SmarterMail's connections per IP per minute. Not sure if SmarterMail supports this type of throttling.
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CLEBER SAAD Replied
Do not support that. If you like, install a linux + postfix and make that an relay of SM with these configuration ;-)
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Paul Blank Replied
Still curious as to what kind of email, and how many emails, over what period, causes this "too many concurrent connections" condition.  Seems to me that unless it was quite a large volume, it would not really be much of an issue with RoadRunner (Time Warner). 
 
Hence my suspicion that it's some kind of hijack. Is it possible that another machine on your LAN (or process on the same server as SM?... usually this does not happen) is acting as an SMTP sender - traffic going out the same WAN IP address?
 
It would be interesting to see the RoadRunner incoming SMTP logs. I know, I know, fat chance of that happening!
 
 
 
 
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Ronald Raley Replied
I have curiously updated this particular customer's SmarterMail IP address. I will report back. Thanks!
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Ronald Raley Replied
The IP address change resulted in the same kickbacks.
 
I called Time Warner and the customer rep insisted that I give her an account number.  Tried to explain that I am not a customer, but run a mail server trying to contact their customers.  They won't give me any information and said the customer would need to call in.  Dead end.
 
Tried contacting the company they hired to block out the world, Return-Path.  They don't answer the phone and I had to leave a message.  Also submitted their contact form.
 
I am now actively trying to get a feedback loop because it says that rate limits are increased to those who have a feedback loop.  But it has been pending approval since 3/29.
 
We basically have a membership database system that sends e-mail to 40 or 50 rochester.rr.com addresses at a time, based on entries made by members.  Very simple.
 
Ron
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Merle Wait Replied
Hi Ron, just curious if there was any update on this issue with RR.COm? Matter of fact, how do you find the place to join their feedback loop?
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Ronald Raley Replied
Resolution!  Getting an approved feedback loop seems to have fixed the "too many concurrent connections" issue.  Hopefully this thread will help other SmarterMail server admins if they find themselves in a similar situation.
 
Thanks!
Ron
 
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Ronald Raley Replied
Feedback loop information is here: http://postmaster.rr.com
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Paul Blank Replied
Fascinating. I went to that page (actually http://postmaster.rr.com/fbl). So even though Time Warner says that FBL is not a whitelist, it just might act as one.

Just to make sure all was OK at this end with our SM server, I found us a rr.com email address to use for testing, and sent mail to/from that address without incident. So clearly we aren't blacklisted (yet). I will probably go ahead and "enroll" in their FBL program anyway. Thanks for the info!

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