Bonjour, Il s'agit de la norme 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. As a result, the receiver-SMTP will not have to perform MX resolution on this name in order to validate the HELO parameter. 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. DISCUSSION: Verifying the HELO parameter requires a domain name lookup and may therefore take considerable time. An alternative tool for tracking bogus mail sources is suggested below (see "DATA Command"). Note also that the HELO argument is still required to have valid <domain> syntax, since it will appear in a Received: line; otherwise, a 501 error is to be sent. IMPLEMENTATION: When HELO parameter validation fails, a suggested procedure is to insert a note about the unknown authenticity of the sender into the message header (e.g., in the "Received:" line). Cordialement, Mickaël Bourneuf http://www.celeonet.fr ----- Original Message ----- From: Michel Arboi To: Xavier Beaudouin Cc: [email protected] Sent: Friday, November 24, 2006 9:31 AM Subject: Re: [FRnOG] Smtp de Wanadoo On Fri Nov 24 2006 at 08:49, Xavier Beaudouin wrote: > Normalement, mais je me souviens plus de la RFC... le ehlo doit être > un FQDN valide qui pointe soit sur un A, soit sur un MX avec > évidement un PTR associé. Le RFC 2821 dit quelque chose dans ce genre au § 4.1.1.1 : "The argument field contains the fully-qualified domain name of the SMTP client if one is available. In situations in which the SMTP client system does not have a meaningful domain name (e.g., when its address is dynamically allocated and no reverse mapping record is available), the client SHOULD send an address literal (see section 4.1.3), optionally followed by information that will help to identify the client system " -- PGP key ID : 0x0BBABA91 - 0x1320924F0BBABA91 Fingerprint: 1048 B09B EEAF 20AA F645 2E1A 1320 924F 0BBA BA91 --------------------------- Liste de diffusion du FRnOG http://www.frnog.org/
