Need email server aid

Christopher Chan christopher.chan at
Fri Apr 23 01:52:26 UTC 2010

On Friday, April 23, 2010 12:48 AM, Markus Schönhaber wrote:
> 22.04.2010 16:10, Chuck Kuecker:
>> Markus Schönhaber wrote:
>>> Above, you said that the embedded system is in your local network. But
>>> this log excerpt shows a client connecting from, i. e. an
>>> IP that is neither in nor Therefore it's not
>>> contained in the IP ranges you configured as mynetworks and
>>> permit_mynetworks doesn't apply.
>> OK. I see that. is my static IP from my ISP. When I
>> resolve '', that's what comes up. I certainly don't want
>> just anyone sending email to that IP to be able to relay!
> That's all fine, but I don't see why your embedded device should connect
> to your mail server *from* - unless the mailserver the log
> excerpt comes from is outside of your local net.
> Maybe you should provide some info about how your network is set up and
> which mailserver you try to access how.

It is simple really. He has a static ip which he uses for his domain mx.

Therefore, the ubuntu box is the natting gateway for his network which 
also runs the postfix in question for his domain and has an internal ip 
address of which may or may not be his internal network's 
gateway ip address. So when the embedded system connects to his postfix, 
it connects to the static ip and the source ip address appears as the 
source ip because it has been nat'ed.

More information about the ubuntu-users mailing list