Cannot connect to Mail server.... sometimes

[Peter Downes]

Hi

My mail app 'sometimes', just 2 or 3 times a day, cannot connect to my mail server and reports a connection error. Five minutes later it is fine. I check very often.

A client reports they cannot connect more frequently - often - and for longer periods. An hour or so at a time.

So I cannot say that the server does not have problem. But I cannot understand why they have greater connectivity problems than I.

Any ideas or where I can look for problems?
Thank you

 

[UFHH01]

Hi Peter Downes,

you can see issues/failures/errors/problems in your mail - logs.

Plesk for Linux services logs and configuration files ( KB - article: 111 283 )​

To extend the messages in your log - files, you can always change the log - level to another mode ( for example debug - mode ), so that you get a more verbose output. Please see "http://www.postfix.org/postconf.5.html" for more information about it.

 

[Peter Downes]

Ah Ha. Er any suggestions on which logs I start with. There seems to be a few to do with mail.

 

[Dave W]

Hi Peter,

You are either using qmail or postfix, either way your mail log is at /usr/local/psa/var/log/maillog

 

[Peter Downes]

Thanks. Looks like I am using POSTFIX

I'm not sure if this is the best place to troubleshoot my mail logs so please tell me if not.

I see these lines every 12 seconds or so:

Where <DOMAIN> replaces a domain hosted on the VPS. There is no mail account set up for test@<DOMAIN>. There is no MX record set for <DOMAIN> pointing to the server.

Apr 5 06:07:23 vps19193315 postfix/smtpd[23133]: connect from unknown[185.22.173.***]
Apr 5 06:07:24 vps19193315 plesk_saslauthd[14036]: No such user 'test@<DOMAIN>' in mail authorization database
Apr 5 06:07:24 vps19193315 plesk_saslauthd[14036]: failed mail authenticatication attempt for user 'test@<DOMAIN>' (password len=8)
Apr 5 06:07:24 vps19193315 postfix/smtpd[23133]: warning: unknown[185.22.173.***]: SASL LOGIN authentication failed: authentication failure
Apr 5 06:07:24 vps19193315 postfix/smtpd[23133]: lost connection after AUTH from unknown[185.22.173.***]
Apr 5 06:07:24 vps19193315 postfix/smtpd[23133]: disconnect from unknown[185.22.173.***]

Perhaps I should stop this - not sure how.
Thanks

 

[Peter Downes]

I've blocked the IP 185.22.173.*** in my firewall.

 

[Lloyd_mcse]

Hi @Peter Downes
I would suggest you install Fail2Ban from the Plesk installer, either in the UI...

Plesk -> Tools & Settings -> Updates & Upgrades

Or via the CLI like so...

Install

/usr/local/psa/admin/bin/autoinstaller --select-product-id plesk --select-release-current --install-component fail2ban

Uninstall

/usr/local/psa/admin/bin/autoinstaller --select-product-id plesk --select-release-current --remove-component fail2ban

I hope that helps
Regards...

 

[Peter Downes]

would suggest you install Fail2Ban from the Plesk installer

OK Will do

 

[Peter Downes]

I found this thread
https://talk.plesk.com/threads/cour...nnection-after-some-hours.208768/#post-560015

I too see this error in my logs
--
Unexpected SSL connection shutdown.
--

I looked at my copy of

It had
--
MAXDAEMONS=40
MAXPERIP=4
--

I know my clients with problems connecting has 11 accounts behind the same IP address.

So I downloaded using ftp and changed to:-
MAXDAEMONS=80
MAXPERIP=60

And uploaded. (I wonder if its ok to do via FTP?)

I've then tried to restart IMAP services following this article.
https://kb.plesk.com/en/113841

But I get strange output from the CLI

--
[root@mail ~]# cp -a /etc/courier-imap/imapd{,.backup}
[root@mail ~]# /etc/init.d/courier-imapd restart
: command not foundmapd: line 23:
....(etc etc)
: command not foundmapd: line 462:
Stopping Courier IMAP server:
--


And then nothing........ But Email is still working so phew.

Any suggestions welcome.
Thanks

 

[Lloyd_mcse]

To restart Courier run...

/etc/init.d/courier-imapd restart

/etc/init.d/courier-imaps restart

/etc/init.d/courier-pop3d restart

/etc/init.d/courier-pop3s restart

/etc/init.d/courier-authdaemon restart

Regards

Lloyd

 

[Peter Downes]

Thanks Lloyd but I guess something is not right on the VPS

I get
[root@mail ~]# /etc/init.d/courier-imapd restart
: command not foundmapd: line 23:
....[lots of command not foundmapd: line here]
: command not foundmapd: line 460:
: command not foundmapd: line 462:
Stopping Courier IMAP server:

Time to raise a support ticket to say I cannot restart Courier?

 

[Lloyd_mcse]

Oh you downloaded the file and edited, sorry I missed that, that possibly changed the format of the file, You can try running...

dos2unix /etc/courier-imap/imapd

And then start courier. But since you have the backup file, just restore it.

You can then set MAXIP in the Plesk panel...

Plesk -> Tools & Settings -> Mail Server Settings

I hope that helps
Regards

Lloyd

Note: If you want to download files and edit them, best use something like Notepad++ and set it up for a UNIX environment. But you are better off learning vi.

 

[Peter Downes]

Ah you are right. I changed the format of the file. Now I can restart.
Thanks so much

 

[Peter Downes]

Note: If you want to download files and edit them, best use something like Notepad++ and set it up for a UNIX environment. But you are better off learning vi.

Thanks for the tip. I was just using the WinSCP editor.

 

[Lloyd_mcse]

Oh good, glad you got it started
No problem, always happy to help
Regadrs

Lloyd

 

[Peter Downes]

You can then set MAXIP in the Plesk panel...
Plesk -> Tools & Settings -> Mail Server Settings

Oh boy knowing that would have saved me a few hours.