>> Here is my configuration: https://pastebin.com/EKHvEveC
> postconf -n
> would be more appropriate, I think
Here it is : https://pastebin.com/efFJb2Sq
> That looks wrong. Where is the first EHLO response line? The above
> starts in the middle of the response.
>
> Can you share a packed dump OFF-LIST so I can see what happens between
> SENDING ehlo and receiving the reply? The entire TCP connection would
> be best.
>are you sure postfix sees exactly this conversation?
>I don't see the SIZE= parameter in MAIL FROM:
Correct me if I’m wrong, but I think this is because I use version 2.11 of
postfix and this feature has been introduced in version 3.0.
>Postfix stores size information in the queue file. What size does the
>queue manager log fot this specific message?
Here are the information in queue file, as shown by a “postcat –q” on the
message queue ID :
*** ENVELOPE RECORDS deferred/3/2/A/32A559F491 ***
message_size:
>Postfix sends "SIZE=" in "MAIL FROM" unless it is going to do 8bit to 7bit
>downgrade:
>(source code removed)
>So it would appear (if your reported transcript is accurate) that
>Postfix did not believe the peer to be 8BITMIME-capable. Since
>the SMTP server's EHLO
> You really should not make up facts out of thin air, however popular that
> might be these days. Support for sending "SIZE=" in Postfix is at least
> 19 years old, with the MIME downgrade suppressing dating back 11 years.
>
> Which suggests that your end (on an RFC1918 IP address of 172.17.25.35)
> is behind a NAT firewall, which could part of the problem. The
> SMTP server however does not seem to be reachable from Internet at
> large, so the networking topology here is unclear.
Indeed, only our servers are able
