How to hide sender server IP in smtp headers?

Question

linux

There is a task: to configure the sending of e-mail in such a way that the external ip address of the mail server in the smtp headers indicates fake or local.
Given a Linux server (A) with exim installed.
You only need to send.
I thought about this: this server is connected to a corporate vpn network, what if I set up another smtp server on server (B) that I can donate, i.e. light IP.
To what extent such a scheme will be efficient: server A sends a letter to server B via vpn (local ip), and server B is already sending. What will be the ip in the headers?

I will be glad to any options.
Thank you.

Answer 1

The solution that suits me so far:
On the server (B) (openvpn is configured, it is a vpn server of the corporate vpn network), add the following line to the config for the server (A):

push "route ip_smtp_relay 255.255.255.0"

And enable NAT on it.
Thus, server A connects to the hoster's smtp-relay through server B and the external IP of server B is visible in the headers.

Answer 2

Use third-party mail forwarding services? Gmail for example.

Answer 3

As far as I understand, ip from the SMTP session is substituted into the Received header. And there it is already difficult to fake it, at least because there are checks for DNS PTR and SPF.

Answer 4

I didn’t understand something, why can’t you send a test letter along this chain, look at its headers, and configure server B to hide unwanted ones?

Answer 5

It seems that the whole chain of ip addresses is glowing in general. Output. Send mail through an anonymous service on the net, and enter your email address in the sender's address.