Topic: Remote host said: 451 Upstream SMTP server not available/

[jonson]

Hi guys in sme server sometimes i cannot send email over outlook using sme server 8.x
when i send message it not reach why
using putty i write the following command
tail -f /var/log/qmail/current
and in messages i notice that message show to me
deferral: Connected_to_127.0.0.1_but_greeting_failed./Remote_host_said:_451_Upstream_SMTP_server_not_available/
This problem is repeated every times it work may be one week then show after this also
email send then stop
How to solve this problem and what can make that problem
my settings is already fixed but the problem sending email is ok working some period
and some period not work
and after that come
can you tell me what problem

[mmccarn]

My first guess is that your SME server is relaying outbound email through an external SMTP server, and that the external server has a daily, weekly, or monthly limit on the number of emails you are allowed to relay.

Some ISPs set this daily limit quite low (100 emails per day), but will raise it if asked.  Or, your relay limit may be adequate, but you may have an infected workstation or email routing loop relaying a high number of outbound email.

Here is an old bug discussing the same error that you're seeing with some potential troubleshooting steps:
http://bugs.contribs.org/show_bug.cgi?id=5854

Here are some wiki resources on general email troubleshooting and monitoring:
http://wiki.contribs.org/Mail_log_file_analysis
http://wiki.contribs.org/Email_Statistics

[jonson]

Thank you for reply
if i need to increase limit what i do

[jonson]

And How to increase limit
and what i o to increase

[Stefano]

since is a limit imposed by ISP, you must call your ISP's helpdesk, you can't do anything on your side (but, please check you have no infected pc on your lan)

[jonson]

What i do to check that no infected pc in my workstation

[Stefano]

first of all disconnect your lan from internet

then, power on each client and scan it with a good and uptodated antivirus..

[jonson]

Thank you for reply
if i call isp what i will tell them about my request

[jonson]

I call my isp it tell me your ip is in our firewall and we remove it
then i test it work one hour then after this not work again
then i call them again he tell me your ip in black list and we remove it from black list and test it
i test it it work one hour then not work again
please what i do in this case
i don't know can you give me suggestions or solutions to this problem

[Stefano]

if your ip is in some BL you have a problem on your side

did you check your clients?
is your SME running any kind of website?

if you want help, you must help us to help you

[jonson]

Thank you for reply
what is the meaning of sme running any kind of website

[Stefano]

jonson:

does your SME server act as a public web server? did you setup any kind of CMS (i.e. wordpress, joomla, $whatever) on your SME?

moreover: I see only questions coming from you, but no answers.. it's quite difficult to help you

[jonson]

Thank you for reply
no it is for email server only
not using for any thing like web or sharing
only mail server
and i installed in every computer eset end point antivirus

[jonson]

How i know my ip in black list and how to remove it from black list

[janet]

jonson

For starters go to
https://www.spamhaus.org/

Please do not ask us how to do it, you need to read the information provided on that website, it tells you everything you need to know.