Recipient address rejected: Service is unavailable

[solutec]

Hello,

after installation we tried to send an Email through the system, but we got the following error:

NOQUEUE: reject: RCPT from gw.soluma.loc[192.168.0.10]: 450 <test@solutec.de>: Recipient address rejected: Service is unavailable; from=<hans@wurst.de> to=<test@solutec.de> proto=SMTP helo=<gw>

The domain in the Licence-File is solutec.de
The name of the system is proxmox.soluma.loc

Thanx.
Michael

 

[christian]

Hello Michael!

Do you have this problem with outgoing or with incoming e-mails?

Remember outgonig e-mails have to use port 26 (standard configuration at the proxmox mail gateway. see your mail server for correct configuration) and incoming should use port 25.

Please let me now if this was the reason for your error.

regards,
christian

 

[solutec]

Hello Christian,

i have this problem with incoming Mails.
After a reboot sometimes it works and sometimes not.
Here is a dialog with the port 25 of our proxmox.
Why does it accept one sender and not the other:

[root@gw root]# telnet 192.168.0.8 25
Trying 192.168.0.8...
Connected to 192.168.0.8.
Escape character is '^]'.
220 proxmox.soluma.loc ESMTP Proxmox (Proxmox)
helo gw
250 proxmox.soluma.loc
mail from: a@example.com
250 Ok
rcpt to: mm@XXXXX.XXX
450 <mm@solutec.de>: Recipient address rejected: Service is unavailable
quit
221 Bye
Connection closed by foreign host.

[root@gw root]# telnet 192.168.0.8 25
Trying 192.168.0.8...
Connected to 192.168.0.8.
Escape character is '^]'.
220 proxmox.soluma.loc ESMTP Proxmox (Proxmox)
helo gw
250 proxmox.soluma.loc
mail from: b@example.com
250 Ok
rcpt to: mm@XXXXX.XXX
250 Ok

Thanx.
Michael

-----------------------
Post edited by Christian on 07.05.2005. (To protect privacy, I have changed the email addresses in your post)

 

[christian]

Hello Michael!

First no panic, that is a normal behavior! The proxmox mail gateway uses greylisting as an anti-spam technique. On the web configuration interface you can turn greylisting on and off.

You can read the white paper about greylisting on http://projects.puremagic.com/greylisting/whitepaper.html to understand how it works and why these 450 Recipient address rejected: Service is unavailable error occurs.

I have send you a short pdf description of greylisting in german (part of my diploma thesis) to your e-mail address. This should explain it.

We recommend to use greylisting, because it is a very very powerful technique.

Any further questions are welcome.

regards,
Christian

 

[solutec]

Hello Christian,

ok, that explains it. After Disabling Greylisting it works.
Our Problem is, we can`t use greylisting because we get our emails via pop. So our Pop-Server fetches the emails and if he can not send it to the proxmox, he will try it later, cause the email is still in the inbox of our provider.
So I think for us: Your technic only works if our provider uses it, or we build up our own Mailserver.

Greetings
Michael