On 6/30/20 9:49 PM, Wietse Venema wrote:
Istvan Prosinger:
Hi, I hope this letter finds you well,
I have Postfix behind NAT, and added one failover IP to the main router.
I wanted to "get by cheaply" by just doing something like
iptbales -t nat -I POSTROUTING -p tcp --dport 25 -j DNAT --to <backup ip>
on the firewall machine.
So, all well, the only problem is that Postfix in this case has a wrong HELO
compared to the rDNS that I have defined
for the <backup IP>
It does throw a warning that the <backup IP> doesn't resolve to it's hostname,
but I'm not sure if I can define some
kind of helo_host_maps ;) to resolve this.
At this point, I wouldn't mind if someone pinpoints me to the right direction.
Postfix does not compare the HELO command argument with forward or
reverse DNS information.
Wietse
Antispam engines on the recipient side do
best,
Istvan
