I've questioned to the support and they replied:
It appears that your configuration within your Linode is correct, and your services are listening on the correct ports. It is possible that there is some type of port filtering or other blocking going on at your ISP's level. Unfortunately, troubleshooting that would be beyond our scope of support.

I would recommend reaching out to your internet service provider in order to query whether they might be blocking common IMAP/SMTP ports. Additionally, I would also recommend reaching out to the Linode Community for additional assistance with your configuration.

And I use Foxmail client, I did it good before, but this time it fails and it shows I have to check the server, proxy,and internet environment,, I can add other email to the client successfully..

Could anybody please tell me how to set the sending server and the receiving server
for example ; Gmail use pop.gmail.com and smtp.gmail.com
My domain is meesk.com ,, I remember I setted them both as mail.meesk.com , but now it didn't work

What mail client are u guys using ?? could anybody recommend one ?

Thanks in advance

meesk.
When I scan your IP (198.58.96.51) I do not see any of the ports for SMTP (25 or 587), POP (110 or 995) or IMAP (143 or 993) responding. Do you have a firewall (such as iptables) configured?

Yeah, I get the same results; only port 22/80/443 (of the common ports) are open. It seems you have a firewall that's blocking traffic.

_________________
Rgds
Stephen
(Linux user since kernel version 0.11)

A firewall ? How can I fix it ?
I blocked a list of IP from my site before,and now I cancel it

meesk, we don't know that the issue is a firewall. We're asking you if you have one set up, and if so which one & what is your config?

Did you follow this? https://library.linode.com/securing-you ... a-firewall

I can now see your server's SMTP, IMAP and POP instance.

PORT    STATE SERVICE
22/tcp  open  ssh
25/tcp  open  smtp
80/tcp  open  http
993/tcp open  imaps
995/tcp open  pop3s

So you should be able to get your mail.

However, some ISPs block outgoing port 25. Normally you'd also want to start up a "submission" listener on port 587; configure this to allow AUTHENTICATED traffic only.

At this point you should be able to send/receive email from your client.

_________________
Rgds

Stephen

(Linux user since kernel version 0.11)

It's OK now after flushing the iptables told by the linode service

Thanks guys !

Hi
I build another mail server with 66.228.56.38
and still the psotfix devecot mail server , when I set an email to the new mailbox I build,
the mail.log file shows:
Oct 15 07:43:47 custom1 dovecot: master: Dovecot v2.2.9 starting up (core dumps disabled)
Oct 15 07:43:47 custom1 dovecot: ssl-params: Generating SSL parameters
Oct 15 07:43:50 custom1 postfix/master[629]: daemon started -- version 2.11.0, configuration /etc/postfix
Oct 15 07:43:55 custom1 dovecot: ssl-params: SSL parameters regeneration completed
Oct 15 23:49:37 custom1 postfix/master[629]: terminating on signal 15
Oct 15 23:49:37 custom1 postfix/master[22201]: daemon started -- version 2.11.0, configuration /etc/postfix
Oct 15 23:53:12 custom1 postfix/master[22201]: terminating on signal 15
Oct 15 23:53:12 custom1 postfix/master[22382]: daemon started -- version 2.11.0, configuration /etc/postfix
Oct 15 23:53:44 custom1 postfix/postmap[22395]: fatal: open /etc/postfix/mysql-virtual-alias-maps.cf: No such file or directory
Oct 15 23:55:50 custom1 postfix/postmap[22423]: fatal: open /etc/postfix/mysql-virtual-alias-maps.cf: No such file or directory
Oct 15 23:59:11 custom1 postfix/master[22382]: terminating on signal 15
Oct 15 23:59:12 custom1 postfix/master[22679]: daemon started -- version 2.11.0, configuration /etc/postfix
Oct 16 00:01:49 custom1 postfix/master[22679]: terminating on signal 15
Oct 16 00:01:49 custom1 postfix/master[22917]: daemon started -- version 2.11.0, configuration /etc/postfix
Oct 16 00:50:01 custom1 dovecot: config: Warning: Killed with signal 15 (by pid=1 uid=0 code=kill)
Oct 16 00:50:01 custom1 dovecot: log: Warning: Killed with signal 15 (by pid=1 uid=0 code=kill)
Oct 16 00:50:01 custom1 dovecot: master: Warning: Killed with signal 15 (by pid=1 uid=0 code=kill)
Oct 16 01:00:09 custom1 postfix/smtpd[23391]: connect from unknown[2600:3c00::f03c:91ff:fe6e:f08]
Oct 16 01:00:09 custom1 postfix/smtpd[23391]: DD69316095: client=unknown[2600:3c00::f03c:91ff:fe6e:f08]
Oct 16 01:00:09 custom1 postfix/cleanup[23398]: DD69316095: message-id=<201410161600054046260@meesk.com>
Oct 16 01:00:09 custom1 postfix/qmgr[22921]: DD69316095: from=<sales@meesk.com>, size=1806, nrcpt=1 (queue active)
Oct 16 01:00:09 custom1 postfix/smtpd[23391]: disconnect from unknown[2600:3c00::f03c:91ff:fe6e:f08]
Oct 16 01:00:09 custom1 postfix/lmtp[23401]: DD69316095: to=<info@custom4u.club>, relay=none, delay=0.04, delays=0.03/0.01/0/0, dsn=4.4.1, status=deferred (connect to custom1.custom4u.club[private/dovecot-lmtp]: No such file or directory)
Oct 16 01:03:30 custom1 postfix/anvil[23394]: statistics: max connection rate 1/60s for (smtp:2600:3c00::f03c:91ff:fe6e:f08) at Oct 16 01:00:09
Oct 16 01:03:30 custom1 postfix/anvil[23394]: statistics: max connection count 1 for (smtp:2600:3c00::f03c:91ff:fe6e:f08) at Oct 16 01:00:09
Oct 16 01:03:30 custom1 postfix/anvil[23394]: statistics: max cache size 1 at Oct 16 01:00:09
Oct 16 01:06:50 custom1 postfix/lmtp[23503]: DD69316095: to=<info@custom4u.club>, relay=none, delay=400, delays=400/0.01/0/0, dsn=4.4.1, status=deferred (connect to custom1.custom4u.club[private/dovecot-lmtp]: No such file or directory)
Oct 16 01:16:50 custom1 postfix/lmtp[23530]: DD69316095: to=<info@custom4u.club>, relay=none, delay=1001, delays=1001/0.01/0/0, dsn=4.4.1, status=deferred (connect to custom1.custom4u.club[private/dovecot-lmtp]: No such file or directory)
Oct 16 01:36:50 custom1 postfix/lmtp[23598]: DD69316095: to=<info@custom4u.club>, relay=none, delay=2200, delays=2200/0.02/0/0, dsn=4.4.1, status=deferred (connect to custom1.custom4u.club[private/dovecot-lmtp]: No such file or directory)


could anyone tell me how is it going pls ??
and I can't login the new mail account with my mail agent client,,
I don't know how to set the appropriate POP3 or IMAP , because I tried all and it didn't work ...
I need your help

and the file has been already created
/etc/postfix/mysql-virtual-alias-maps.cf:
private/dovecot-lmtp

everything went well when I was following the guide

I sent an email to the new mail account and i got this message:

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The mail system

<info@custom4u.club>: mail for custom4u.club loops back to myself

what's the problem ?