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Author Topic: Outgoing smtp connections very slow  (Read 21106 times)

hlesta

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Outgoing smtp connections very slow
« on: December 21, 2017, 06:40:36 AM »

Hello there,

I have experiencing slow outgoing smtp connections, I add the following points that I can see.

- Always the connections are alive, and these connections are keeped in 2000 but never down
- The rate of delivery for minute is 200 emails (very slow), I have more than 100 vmtas and more of 300 ips at this moment

The last change in our infrastructure was add four IPs in pmta network interface, these Ips were in another postfix infrastructure.

Is it possible that, this problem is due to a network problem?

In pmta log I can see multiple extraneous IPs that try to connect with us? Is it normal or could be a ddos attack?

Thank you!
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CaLViN

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  • Hasan Kurtoglu
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Re: Outgoing smtp connections very slow
« Reply #1 on: December 21, 2017, 06:41:34 AM »

What errors do you get from ISPs ?
connection timeouts,deferrals,blocks ?
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hlesta

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Re: Outgoing smtp connections very slow
« Reply #2 on: December 21, 2017, 06:50:48 AM »

Hi Hasan,

All corporate emails returns StatusDnsNameError resolving domain

Hotmail:

-Error: "451 4.7.0 Temporary server error. Please try again later. PRX3 NextHop: BN3-NAM01b.hub.protection.outlook.com [BN3NAM01FT052.eop-nam01.prod.protection.outlook.com]" while connected from ...

- Connection failed (pollERR), status = ECONNRESET while connected from XXXXXXX to hotmail-com.olc.protection.outlook.com (XXXX)

. Error: "451 4.7.0 Timeout waiting for client input [DB5EUR03FT029.eop-EUR03.prod.protection.outlook.com]" while connected from XXXXX to hotmail-com.olc.protection.outlook.com (XXXXXX)


YAHOO

- Error: "554 delivery error: dd Requested mail action aborted - mta1485.mail.bf1.yahoo.com" while connected from xxxxxxxxxx to mta6.am0.yahoodns.net (xxxxxxxxxx)


GMAIL

- StatusDnsNameError resolving domain-> return bounces : 5.1.2 (bad destination system: no such domain)


Thank you!

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CaLViN

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  • Hasan Kurtoglu
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Re: Outgoing smtp connections very slow
« Reply #3 on: December 21, 2017, 06:52:14 AM »

You have an issue with your connections as you see.
This should be resolved first.
Check DNS resolving and tracert results.
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hlesta

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Re: Outgoing smtp connections very slow
« Reply #4 on: December 21, 2017, 07:07:08 AM »

Hasan,

Thank you! I try to check the connections.

Is it possible that these Ips added were in another network interface and cause connection errors in general?

Regards!
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CaLViN

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Re: Outgoing smtp connections very slow
« Reply #5 on: December 21, 2017, 07:09:27 AM »

Well anything is possible.
You cant reach GMAIL,there you can see the issue. :))
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ReyM

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Re: Outgoing smtp connections very slow
« Reply #6 on: December 21, 2017, 07:32:26 AM »

run a pmta trace command on the VMTAs that are using the new IP addresses. This looks primarily like a DNS issue like Calvin said, or a larger network issue if the new IP's can't get "out" of your area.
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hlesta

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Re: Outgoing smtp connections very slow
« Reply #7 on: December 21, 2017, 01:45:21 PM »

run a pmta trace command on the VMTAs that are using the new IP addresses. This looks primarily like a DNS issue like Calvin said, or a larger network issue if the new IP's can't get "out" of your area.

Hello, thanks

We have detected the problem. We are using a bounce handler via pipe using the following code:

Code: [Select]

<acct-file |/usr/local/bin/python3.6 /opt/emBlue3/App_Main_Popper/PowerMtaPipeEmblue.py -u "popper.embluemail.com" -s "bounces">
    records b, rb
    record-fields b orig,timeLogged, bounceCat,dsnStatus,rcpt,header_X-emmkt
    record-fields rb orig,timeLogged, bounceCat,dsnStatus,rcpt,header_X-emmkt
</acct-file>


When we comment the whole config, pmta starts work fine.

I have attached in this thread a screen capture with a time-out error.

We find a similar error in the following github forum : https://github.com/magicdude4eva/port25-bouncehandler/issues/12

Could you please tell me if this issue is due the pmta version? We have Pmta V4.5

Regards!
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ReyM

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Re: Outgoing smtp connections very slow
« Reply #8 on: December 21, 2017, 01:47:21 PM »

I know people do use the pipe command, but I have found that time and time again under load it will cause issues... it's much better to write the data to disk and use an out of band bounce processor, that's what I do and it lets PMTA do it's job much better.
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hlesta

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Re: Outgoing smtp connections very slow
« Reply #9 on: December 21, 2017, 02:38:09 PM »

I know people do use the pipe command, but I have found that time and time again under load it will cause issues... it's much better to write the data to disk and use an out of band bounce processor, that's what I do and it lets PMTA do it's job much better.

Rey,

Thank you for your feedback I appreciate it. I'll analyze another way to improve this process.

If you have some recomendation more, please let me know


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Port25-Admin1

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Re: Outgoing smtp connections very slow
« Reply #10 on: December 21, 2017, 07:12:38 PM »

You can always test outside of PowerMTA with:

cat acct.csv | yourProgram.py
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Port25-Admin1
------------------
Try the following commands:
Quote
pmta show topdomains --errors
pmta show topqueues --errors
pmta --help

When PowerMTA won't start use:
Quote
pmtad --debug
When all else fails-->support@port25.com

hlesta

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Re: Outgoing smtp connections very slow
« Reply #11 on: December 22, 2017, 08:46:54 PM »

You can always test outside of PowerMTA with:

cat acct.csv | yourProgram.py

Hello Admin,

Thank you for your advice. I'll try to use it to change this issue. I'll like use some software to get reports about exceptions or errors and understand all about it.
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ReyM

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Re: Outgoing smtp connections very slow
« Reply #12 on: December 27, 2017, 08:05:39 AM »

What types of errors etc. are you looking at to capture or do not understand?
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