[ALUG] Strange postfix problem

Chris Green cl at isbd.net
Thu Dec 7 11:59:15 GMT 2017

On Thu, Dec 07, 2017 at 11:28:52AM +0000, Laurie Brown wrote:
> Having looked at the logs, said client is the only person this happens
> to, and there's one consistent feature which is seriously puzzling me.
> Here's a log entry (doctored):
> Dec  6 07:56:57 mg3 postfix/smtpd[28482]: NOQUEUE: reject: RCPT from
> host86-141-***-***.range86-141.btcentralplus.com[86.141.***.***]: 554
> 5.7.1 <****@gmail.com>: Relay access denied; from=<***@****.co.uk>
> to=<****@gmail.com> proto=ESMTP helo=<[]>
> Note the IP address in that last "helo"; it's a non-public one. Each and
> every one of the failures has a seemingly-random non-public IP address
> in it. The IP remains consistent during each "session" but it changes
> every time a new connection is made.
How odd!  How is that client connecting to your system?  I.e. is it
via their ADSL then in to yours, or is your postfix server 'out there'
somwhere and thus not behind a NAT router?  Does the non-local IP make
any sense at either their end or your end?

Should we take this off list?

Chris Green

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