Hey thanks Remo
smtps is an inbound port, they are contacting me - this IP is in Russia
somewhere - so do I want to engage (perhaps, probably not but ..)

I could of course block that IP - but that doesn't help, I'd have to block
endless IPs

I'd like to know what's taking the CPU load, in theory they should be
connecting, supplying a password (perhaps) and sending data
but, there are sometimes bad passwords (2 for the 20th recorded in maillog)

So..
What are they doing the other times and why is it taking so much CPU - if
it is just a port knock, why the CPU

I need to be able to say, they are bad because ... *what is the because* ?

David Bray
0418 745334
2 ∞ & <


On Mon, 20 Apr 2020 at 15:32, Remo Mattei <r...@mattei.org> wrote:

> Hi,
> Can you reach the server?  It maybe blocking you. So what does your queue
> looks like?
>
> Here is mine for example:
>
> # qmHandle -L
> Messages in local queue: 0
> Messages in remote queue: 0
>
> My other server
>
> # qmHandle -L
> 10355792 (19, L)
>   Return-path: r...@qmailxxxxx.com
>   From: Anacron <r...@qmailxxxx.com>
>   To: r...@qmailxxxxx.com
>   Subject: Anacron job 'cron.daily' on qmailxxxxx.com
>   Date: 19 Apr 2020 10:28:28 -0000
>   Size: 509 bytes
>
> 10358746 (6, L)
>   Return-path:
>   From: mailer-dae...@qmailxxxxxx.com
>   To: r...@qmailxxxxxxxx.com
>   Subject: failure notice
>   Date: 19 Apr 2020 11:30:30 -0000
>   Size: 1089 bytes
>
> Messages in local queue: 2
> Messages in remote queue: 0
>
> Just wonder it looks that you are using the SMTPs 465, did you try the 587
> Submission that address and see if it goes?
> Just wonder if this is tight to that service.
>
> Maybe none of the above but just for troubleshooting steps, I would try
> that.
>
> Remo
>
>
> On Apr 19, 2020, at 22:11, David Bray <da...@brayworth.com.au> wrote:
>
> Ok - but after all the investigation etc, this is actually the trigger
> which caught my eye in the first place
>
> How this comes about is:
>
>    1. User say hey I can't send
>    2. I look and see this high CPU load and intermittent failures for
>    client to send
>
> Any thoughts on where to start looking ..
>
>
> <image.png>
>
> my smtp/smtps are currently *10*/11 connections
>
>
> ==> /var/log/qmail/smtp/current <==
> 2020-04-20 05:07:50.207299500 tcpserver: end 29699 status 0
> 2020-04-20 05:07:50.207300500 tcpserver: status: 0/60
>
> ==> /var/log/qmail/smtps/current <==
> 2020-04-20 05:07:54.903665500 tcpserver: status: 9/60
> 2020-04-20 05:07:54.936654500 tcpserver: pid 29725 from 185.50.149.5
> 2020-04-20 05:07:54.936655500 tcpserver: ok 29725 dev.brayworth.com:
> 172.105.181.18:465 :185.50.149.5::5622
> 2020-04-20 05:08:00.108657500 tcpserver: status: 10/60
> 2020-04-20 05:08:00.152909500 tcpserver: pid 29734 from 185.50.149.5
> 2020-04-20 05:08:00.152910500 tcpserver: ok 29734 dev.brayworth.com:
> 172.105.181.18:465 :185.50.149.5::62006
> 2020-04-20 05:08:05.172650500 tcpserver: status: *11*/60
> 2020-04-20 05:08:05.208983500 tcpserver: pid 29740 from 185.50.149.5
> 2020-04-20 05:08:05.208984500 tcpserver: ok 29740 dev.brayworth.com:
> 172.105.181.18:465 :185.50.149.5::19686
> 2020-04-20 05:08:13.601336500 tcpserver: end 29690 status 256
> 2020-04-20 05:08:13.601337500 tcpserver: status: 10/60
>
> David Bray
> 0418 745334
> 2 ∞ & <
>
>
> On Sun, 19 Apr 2020 at 10:04, David Bray <da...@brayworth.com.au> wrote:
>
>> Thanks Eric
>>
>> It's hard to track things but I think I have had success monitoring the
>> /var/log/maillog
>>
>> I'm not sure why I didn't pick this up earlier, I'm already using the
>> fail2ban suggestion of the older qmailtoaster wiki (
>> http://wiki.qmailtoaster.com/index.php/Fail2Ban), actually had a rule to
>> process it and have expanded on this now
>>
>> I've been running email servers most of my working life and still get
>> tripped up by simple stuff
>>
>> Thank for your efforts in this area, it helps to talk things out
>>
>> cheers
>>
>> David Bray
>> 0418 745334
>> 2 ∞ & <
>>
>>
>> On Sun, 19 Apr 2020 at 01:12, Eric Broch <ebr...@whitehorsetc.com> wrote:
>>
>>> It looks like a connect and disconnect. If there was authentication
>>> you'd see it. I don't think you have anything to worry about here. I'm not
>>> saying there's not some jerk out there messing with your smtps...just
>>> saying it may be harmless. That said, do you have a good firewall in place
>>> that prevents DOS attacks. I use Sonicwall myself but you can do the same
>>> thing as others have shown with iptables.
>>>
>>> Does anyone know how to do the same with the stock firewalld on COS7/8?
>>> On 4/17/2020 11:49 PM, David Bray wrote:
>>>
>>> sure - thanks for replying, this comes in waves taking the server to
>>> it's maximum at times
>>>
>>> as far as I can see this only logs are this:
>>>
>>> ==> /var/log/qmail/smtps/current <==
>>> 2020-04-18 05:04:48.450871500 tcpserver: status: 6/60
>>> 2020-04-18 05:04:48.480785500 tcpserver: pid 13339 from 141.98.80.30
>>> 2020-04-18 05:04:48.480787500 tcpserver: ok 13339 dev.brayworth.com:
>>> 172.105.181.18:465 :141.98.80.30::25638
>>> 2020-04-18 05:04:52.797644500 tcpserver: status: 7/60
>>> 2020-04-18 05:04:52.830767500 tcpserver: pid 13340 from 141.98.80.30
>>> 2020-04-18 05:04:52.830768500 tcpserver: ok 13340 dev.brayworth.com:
>>> 172.105.181.18:465 :141.98.80.30::14862
>>> 2020-04-18 05:04:57.248902500 tcpserver: status: 8/60
>>> 2020-04-18 05:04:57.304003500 tcpserver: pid 13342 from 141.98.80.30
>>> 2020-04-18 05:04:57.304006500 tcpserver: ok 13342 dev.brayworth.com:
>>> 172.105.181.18:465 :141.98.80.30::9646
>>> 2020-04-18 05:05:01.854790500 tcpserver: status: 9/60
>>> 2020-04-18 05:05:01.902265500 tcpserver: pid 13345 from 141.98.80.30
>>> 2020-04-18 05:05:01.902266500 tcpserver: ok 13345 dev.brayworth.com:
>>> 172.105.181.18:465 :141.98.80.30::54058
>>> 2020-04-18 05:05:09.729711500 tcpserver: end 13338 status 256
>>> 2020-04-18 05:05:09.729713500 tcpserver: status: 8/60
>>> 2020-04-18 05:06:05.965715500 tcpserver: end 13342 status 256
>>> 2020-04-18 05:06:05.965716500 tcpserver: status: 7/60
>>> 2020-04-18 05:06:06.141272500 tcpserver: end 13340 status 256
>>> 2020-04-18 05:06:06.141273500 tcpserver: status: 6/60
>>>
>>> David Bray
>>> 0418 745334
>>> 2 ∞ & <
>>>
>>>
>>> On Sat, 18 Apr 2020 at 15:41, Eric Broch <ebr...@whitehorsetc.com>
>>> wrote:
>>>
>>>> Can you send the log of one of the "bad" connections?
>>>>
>>>> On 4/17/2020 10:59 PM, David Bray wrote:
>>>>
>>>> I can see I'm getting hammered on my smtps port
>>>>
>>>> How can I mitigate this?
>>>>
>>>> I can see the IP's in /var/log/qmail/smtps/current
>>>>
>>>> *but where do I actually see that the smtp auth actually fails ?*
>>>>
>>>> or do I need to increase the logging somewhere ?
>>>>
>>>> if I tail -f /var/log/dovecot.log
>>>>
>>>> I can see the imap and pop failures
>>>>
>>>> thanks in advance
>>>>
>>>> David Bray
>>>> 0418 745334
>>>> 2 ∞ & <
>>>>
>>>>
>

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