Noproxyprotocol, proxyprotocol Channel Options
Proxy protocol support
New in MS 220.127.116.11, the
proxyprotocol enables server-side use of the proxy protocol. Note that the proxy protocol is not negotiated; enabling it on the server side will cause connections to hang if the client doesn't send the necessary PROXY command. Presently, only proxy protocol v1 (text format) is supported.
At present only the SMTP and MMP servers support the proxy protocol for incoming connections. This is supported with SMTP and Submission protocols (port 25 & 587), but works incorrectly with the submissions protocol (port 465) so it's important to make sure any slave channel used to offer submissions service is configured with noproxyprotocol.