first time posting. This forum and it has helped me many many times.
I was looking to for some advice / views on a problem I’m having.
The server is relatively old, Debian 6 to be exact but upgrading right isn’t an immediate option due to some essential legacy applications (I’m looking into containing some of these via docker in future)
Outgoing emails have always been sent using Exim using our isp smarhost through an email account, authenticated IP address and by encrypted password. This has always worked just fine. However due to email volumes we have had to look into moving away from our isp and to a dedicated relay provider.
Our new relay host is authenticated by IP and can be set up to use TLS. After making the switch via exim’s dpkg-reconfigure things work, often for a few hours. Then I get delayed mail and the following type of error messages.
10:15:12 TLS error on connection to relayhost [relay ip] (recv): A TLS packet with unexpected length was received. 10:15:12 Remote host relayhost [relayip] closed connection in response to MAIL FROM:<our email> SIZE=2136
I admit here my knowledge of Exim is limited and I usually turn to sites like this for advice
I have tried making a file /etc/exim4/conf.d/main/00_localmacros, and adding
This worked for a while.
I get the feeling I’m missing something quite fundamental about TLS here. Our relay host have suggested rebuilding exim from source, they will offer technical support on that at a cost in the new year.
For now I have reverted back to the isp method. Any opinions and or advise would be greatly appreciated.