I bought myself a new computer at the end of last week to replace my aging 32 bit machine. I decided to install Debian Testing/Jessie 64 bit from scratch and set it up to match, roughly, what was on my old machine.
I included Postfix which was on my 32 bit machine on the assumption that I could copy the Postfix configuration across and it would work. I have to admit that I find email configuration to be one of the black arts which uses magic incantations.
Needless to say it didn't work. After a bit of research I discovered that putting 'inet_protocols = ipv4' in main.cf enabled me to send emails.
Some of the sent emails appear to get to their intended destinations and some don't with messages as under:
mywife@gmail.com: host mx1.spamfiltering.com[212.113.130.124] said: 550 relay not permitted! (in reply to RCPT TO command)
me@myaddress.co.uk: host mx1.spamfiltering.com [72.249.150.158] said: 550 81.151.115.33 is listed on sem-black.rbl.spamrl.com. Please organise removal and retry. (in reply to end of DATA command)
I have obscured some of the details but it should still give an idea. the ip address 81.151.115.33 is btinternet.com our ISP.
Similar emails sent from my old machine don't produce those error messages.
Any suggestions would be much appreciated.