On 5/23/2011 10:19 AM, Jeffs wrote:
On 5/23/2011 11:06 AM, Noel Jones wrote:
The Received: header is added by the receiving system, not
by your server, and always shows the IP of the connection.
If you want each client to have their own identity, each
client will need its own IP. You can't virtualize this.
Understood. Thank you. I do understand virtualization to a
degree although I haven't actually instituted it yet. So you
are saying each sender, as per example, above, would have
their own static IP address and that would show as the
originating IP sender?
If that's what works I will institute that.
Thank you and correct me if my thinking on this is inaccurate.
Cheers.
Yes, if each client needs their own identity, they each need
their own IP. Note this is a limitation of the SMTP protocol,
not postfix. With SMTP, the connection is identified by the
IP, then the name is derived from the PTR hostname of that IP.
That's why you need multiple IPs to support multiple names.
(While it's technically possible to set multiple PTR hostnames
for an IP, there is no mechanism tell the remote client which
hostname applies to "this" connection. So as a practical
matter, it makes no sense to use more than one PTR hostname).
Also note that the accepted practice is for the source IP to
identify itself as the mail service provider, not the client.
-- Noel Jones
