On 21 Mar 2005 at 2:17, Greg A. Woods wrote about
"Re: [exim] Exim server behind NAT r":
|...
| Regardless RFC 1123 is also still the main part of the mandatory host
| requirements standard (part of STD 3), the single most important (though
| as I said, somewhat dated and politically flawed) requirements document
| for all Internet participants. It still reads, in part:
|
| 5.2.5 HELO Command: RFC-821 Section 3.5
|
| The sender-SMTP MUST ensure that the <domain> parameter in a
| HELO command is a valid principal host domain name for the
| client host. [[ .... ]]
And goes on to say:
The HELO receiver MAY verify that the HELO parameter really
corresponds to the IP address of the sender. However, the
receiver MUST NOT refuse to accept a message, even if the
sender's HELO command fails verification.
Look familiar?
- Fred
