Hello everyone, My topics (and problem) is smiliar to https://forum.proxmox.com/threads/change-helo-fqdn-independently-from-server-hostname.44186/ and https://forum.proxmox.com/threads/change-helo-hostname.52582/. We want to change our Helo name to something different then our hostname of proxmox. The reason is that some mailservers who force Helo check are blocking our e-mails currently they see our internal hostname of proxmox server (identical problem as second topic). We have two gateways (on cluster) where we cannot change a smtp_helo_name for these machnies. When we change a smtp_helo_name, cluster system after synchronization overwrites the values, and this way we back to the start position. I've introduced a changes directly in file /etc/postfix/main.cf but this way system overwrites the values. We use a version 5.1-4 Proxmox Gateways.