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=<[192.168.1.80]>
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?