How to send mail from a server, hiding the IP of this server?

Question

System administration

There is a server that is constantly attacked. We use the services of various AntiDDoS services that pass traffic through themselves. But there is a problem: the real IP of the server gets into the headers of sent emails, i.e. attackers can hit directly. We tried to send mail through external services (sendgrid, etc.), but they all add the server IP to the headers. Is there a way to hide the IP?

Answer 1

Take an intermediate server that will contain ONLY mail and either forward through it, cutting out unnecessary headers, or immediately send through it.

Answer 2

1) a VPS is rented,
2) an IP tunnel is configured between the server and the VPS,
3) IP addresses in the tunnel: server=192.168.0.1/30, vps=*.2/30,
4) an SMTP server is launched on the VPS, which listens only to the tunnel interface,
5) all messages are sent to sendgrid,
6) in the headers, instead of the public address of the server, 192.168.0.1 will be visible.

Answer 3

You can do this using the GRE tunnel - your server will go to the Internet through the AntiDDoS server, but not all AntiDDoS services do this.
In PM I can advise those who definitely do)

Answer 4

By the way, can you write your impressions of the anti-ddos services you use?