======== Required information ====
- iRedMail version: 1.8.1
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): iRedAdmin-Pro-MySQL
- Linux/BSD distribution name and version: Debian Wheezy (Debian 3.2.57-3 x86_64)
- Related log if you're reporting an issue:
====

Hi Zhang,
I like have a question about throttling during sending email over SMTP with SSL or STARTTLS. On the user side, there is very long delay for tens seconds (I mean dialog with sending...), usually 20 or 30 sec. Doesn't matter if used Outlook 2010 od Thunderbird 24.4.0.

The server is in the idle state, load is 0.0x to 0.x. There is 32GB of RAM and tvelve cores (Xeon E5-2620).

Mail.log is full of that messages (grep "postfix/smtp" mail.log |grep sent |grep delay |grep -v "relay=local"):
Apr 29 19:52:46 six postfix/smtp[4223]: 3D7241E008A: to=<name@realdomain.cz>, relay=127.0.0.1[127.0.0.1]:10024, delay=27, delays=6.3/0.01/0.01/20, dsn=2.0.0, status=sent (250 2.0.0 from MTA(smtp:[127.0.0.1]:10025): 250 2.0.0 Ok: queued as BA3491E008C)

grep 3D7241E008A mail.log :
Apr 29 19:52:25 six postfix/smtpd[4204]: 3D7241E008A: client=static-82-242-75-126.net.upcbroadband.cz[82.242.75.126], sasl_method=PLAIN, sasl_username=name@realdomain2.cz
Apr 29 19:52:26 six postfix/cleanup[4218]: 3D7241E008A: message-id=<535FE6AB.4090503@realdomain2.cz>
Apr 29 19:52:26 six postfix/qmgr[4030]: 3D7241E008A: from=<admin@realdomain2.cz>, size=678, nrcpt=1 (queue active)
Apr 29 19:52:46 six amavis[4060]: (04060-01) Passed CLEAN {RelayedInternal}, LOCAL [82.242.75.126]:57825 [82.242.75.126] <admin@realdomain2.cz> -> <name@realdomain.cz>, Queue-ID: 3D7241E008A, Message-ID: <535FE6AB.4090503@realdomain2.cz>, mail_id: 27ifQFxam3Or, Hits: -10, size: 678, queued_as: BA3491E008C, 20436 ms
Apr 29 19:52:46 six postfix/smtp[4223]: 3D7241E008A: to=<name@realdomain.cz>, relay=127.0.0.1[127.0.0.1]:10024, delay=27, delays=6.3/0.01/0.01/20, dsn=2.0.0, status=sent (250 2.0.0 from MTA(smtp:[127.0.0.1]:10025): 250 2.0.0 Ok: queued as BA3491E008C)
Apr 29 19:52:46 six postfix/qmgr[4030]: 3D7241E008A: removed

(Note:  name@realdomain.cz and realdomain2 was rewritten by me)

In this exaple the transmission time is 20 sec. On our other server, older and  heavy loaded mail server with postfix (no iredMail), is delay usually from 1 to 5 sec.

Please, do you have any idea? What can be wrong? Is there any problem with message transmission time (entry delay or delays)?

THX for help.
Josef