Hetzner + Proxmox problems with the route?

Question

Debian

I've looked all over the net, but I couldn't find an answer to the problem.

Hetzner has a server, it has proxmox 2
Accordingly, as usual, Hetzner has a main IP of 188.xxx.xxx.15 and a subnet of 178.xxx.xxx.xxx/29, a virtual machine lives on it, hosts everything works fine except for ... mail !

That is, when a virtual machine sends mail from any domain, then instead of the native IP of the virtual machine, the main IP of the server arrives !!!
And if Google, although it swears
Received-SPF: softfail (google.com: domain of transitioning [email protected] does not designate 188.xxx.xxx.15 as permitted sender)
but still accepts mail, then many do not want to accept at all mail in any form :( naturally thinking that they are being sent spam.

The question is, how can this be!
And how can this be fixed?!

Thanks in advance for your help.

Answer 1

You just don’t try to understand how routing works, instead of setting up the correct routing, you set up the correct nat, which is also a masquerade, it’s written in your rules to use all internal ips with the main ip of the server, you get exactly what you did.
Read the hetner's doc carefully, but be sure to read it in English.
Well, in the end, it’s not a shame to read articles on Habré about this.
My article describes how to configure the network
habrahabr.ru/post/158061/

Answer 2

I have exactly copied from Hetzner's documentation:

post-up   iptables -t nat -A POSTROUTING -s '178.xxx.xxx.96/29' -o eth0 -j MASQUERADE
post-down iptables -t nat -D POSTROUTING -s '178.xxx.xxx.96/29' -o eth0 -j MASQUERADE

everything seems to be plowing, but only with the mail what is happening! :(

Answer 3

I did two-way NAT

Answer 4

can you show how?