[Okta Webinar] Learn how to a build a cloud-first strategyRegister Now

x
?
Solved

Exchange minimum retry time

Posted on 2006-06-07
24
Medium Priority
?
3,426 Views
Last Modified: 2012-05-05
I got a call from a customer telling me that our emails to his provider where blocked because we are not complying with the SMTP protocol.
Our server was added to a grey list for anti spamming.

I was told that our email server (EXCHANGE-CGN) is sending retries too quickly.

What did happen?

The provider did check their trace logs:

The remote mail server was busy and did send a busy message to our server.
Our server did then resend the email after 4 minutes.
This is, based on information of the provider, too fast.
I am told by them that The SMTP protocol says that the minimum retry time is 5 minutes.

My question is where can I check to see what the minimum retry time is in exchange.

Thanks,
Rory

0
Comment
Question by:rorybrady
  • 12
  • 6
  • 4
  • +2
24 Comments
 
LVL 35

Expert Comment

by:rakeshmiglani
ID: 16852866
i think there is a setting on the default smtp virtual server which defines the retry interval. have you checked it?
0
 

Author Comment

by:rorybrady
ID: 16853020
Ya I think so all of the settings are set to 10 Min +
0
 
LVL 4

Expert Comment

by:ari24
ID: 16853781
If you recently changed the retry interval, you will need to restart the smtp service for it to take effect.
0
Creating Active Directory Users from a Text File

If your organization has a need to mass-create AD user accounts, watch this video to see how its done without the need for scripting or other unnecessary complexities.

 

Author Comment

by:rorybrady
ID: 16853802
No changes have been made it looks like this was orginally setup using the default settings.
0
 
LVL 4

Expert Comment

by:ari24
ID: 16853885
Do you have multiple outgoing servers? Make sure your retries are coming from the same IP!!!


Also a quick explanation of greylisting:
You werent added to a "grey list"... greylisting is a form of antispam that relies on the fact that most sources of spam dont behave in the same manner as regular mail servers. They basically employ a "fire & forget" type of scheme and will not retry sending a spam if it rejected once. RFC compliant servers will attempt retries after a specified period of time. As long as that time period is longer than the setting on the server doing the greylisting, and the IP of the host attempting delivery, the envelope sender address, and the envelope recipient address are all the same on the retry, the server will accept the message.
0
 
LVL 26

Expert Comment

by:jar3817
ID: 16854254
This doesn't make much sense. Sure you get greylisted the first attempt, and will every other attempt until a certain time limit has passed, which is set by the people who run the server performing the greylisting. Once that specified time is up the next attempt to deliver the message should be accepted. It shouldn't matter that you retry too fast, you could retry every 5 seconds if you want (but I don't recommend) and the message still won't be accepted until the right amount of time has past. But the next time after that limit is up I'll be accepted. So your first retry is too soon, so what? The next one (probably another 4 minutes later) should be accepted.  

If the receiving server is blacklisting you because you retry too soon that is their problem for having their server set too strict. Complaining about a minute here or there is a little rediculous.
0
 

Author Comment

by:rorybrady
ID: 16854457
These are our Delivery Option settings:

First retry interval: 10 min
Second Retry interval 10 min
Third Retry interval 10 min
Subsequent retry interval 15 min
Delay notification 12 hours
Expiration Timeout: 2 days

In my understanding this is how our server should react to a busy message from anouther server. Could this be a problem with the configuration of there server? Or am I not looking in the right place?

thanks for all of your guys/girls help.

cheers,
rory
0
 
LVL 4

Expert Comment

by:ari24
ID: 16854471
Again, do you have multiple outgoing servers? Make sure your retries are coming from the same IP.
0
 

Author Comment

by:rorybrady
ID: 16854496
We have a few outgoing servers as we have many remote offices.

How do I check: "Make sure your retries are coming from the same IP."

0
 
LVL 4

Expert Comment

by:ari24
ID: 16854609
Also, it sounds like you might be using a smtp connector, which would make your delivery retry options useless.
0
 

Author Comment

by:rorybrady
ID: 16854636
How would I check these things?
0
 
LVL 104

Expert Comment

by:Sembee
ID: 16857622
An SMTP Connector doesn't have any retry times on it, so there is nothing to set on there.
Is there anything else installed on this machine? Antivirus, antispam? Something that could be interfering with the traffic?

It appears to me that most deployments of greylisting are flawed. It seems to be the new weapon of choice for spam, but isn't being deployed properly. I have seen greylisting deployed where the SMTP error code sent back wasn't deferred, but failure, meaning that the message was NDR'd.

Simon.
0
 

Author Comment

by:rorybrady
ID: 16862538
There seems to be some conflicting opinions here. air24, it looks like we do have an smtp connector and you say that this makes our delivery options usless. Sembee says that there is no retry times on a connector which is true. So how would an smtp connector render the delivery options useless?

Thanks,
Rory
0
 
LVL 104

Expert Comment

by:Sembee
ID: 16862636
The only reason I can think that the retry times are nullified by the SMTP Connector is if a smart host is being used. In that case the retry times on the smart host server would be what is used.

Simon.
0
 

Author Comment

by:rorybrady
ID: 16862820
You will have to excuse my ignorance on this subject this stuff is pretty new to me. Do you know how I would check the retry times on the smart host?

Thanks,
Rory
0
 
LVL 104

Expert Comment

by:Sembee
ID: 16862836
You can't.
The smart host would be something like your ISPs email server.
Do you have a smart host in the SMTP Connector?

Simon.
0
 

Author Comment

by:rorybrady
ID: 16862984
I think the smart host setup for this connector is our head offices exchange server.


Remote Bridgehead

Server: Head office Exchange server
Virtual Server: Routing

Genral Tab
Connects this routing group with:
Head Office
0
 
LVL 104

Expert Comment

by:Sembee
ID: 16863097
Routing Group connectors and SMTP Connectors are two different things.
However if you have an SMTP Connector with the head office Exchange server as the bridgehead, then it is that SMTP virtual server on that machine that needs to be checked.

Simon.
0
 

Author Comment

by:rorybrady
ID: 16863131
We have our proxy server set up as the smart host. Do you know where I would find the retry times on the smart host?
0
 
LVL 104

Expert Comment

by:Sembee
ID: 16863231
Depends what you are using on the server. If it is IIS, then you will need to look at the SMTP server settings.

Simon.
0
 

Author Comment

by:rorybrady
ID: 16863321
Where in IIS do I change these settings?

I appreciate you patience!
0
 

Author Comment

by:rorybrady
ID: 16863606
This looks like a problem on the clients side. The settings in IIS for Retrys is as follows:

First retry interval: 15 min
Second Retry interval 30 min
Third Retry interval 60 min
Subsequent retry interval 240 min
Delay notification 12 hours
Expiration Timeout: 2 days

What do you think?
0
 
LVL 104

Accepted Solution

by:
Sembee earned 2000 total points
ID: 16863692
Those look like standard settings. Certainly not as short as the time reporting in the original message.

Simon.
0
 

Author Comment

by:rorybrady
ID: 16863926
Thanks fo rall of your help Sembee, you were dinamite!!
0

Featured Post

Restore individual SQL databases with ease

Veeam Explorer for Microsoft SQL Server delivers an easy-to-use, wizard-driven interface for restoring your databases from a backup. No expert SQL background required. Web interface provides a complete view of all available SQL databases to simplify the recovery of lost database

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

With so many activities to perform, Exchange administrators are always busy in organizations. If everything, including Exchange Servers, Outlook clients, and Office 365 accounts work without any issues, they can sit and relax. But unfortunately, it…
Steps to fix “Unable to mount database. (hr=0x80004005, ec=1108)”.
how to add IIS SMTP to handle application/Scanner relays into office 365.
This video demonstrates how to sync Microsoft Exchange Public Folders with smartphones using CodeTwo Exchange Sync and Exchange ActiveSync. To learn more about CodeTwo Exchange Sync and download the free trial, go to: http://www.codetwo.com/excha…
Suggested Courses
Course of the Month18 days, 16 hours left to enroll

834 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question