[Mimedefang] Revisit: Filtering on HELO

Jonas Eckerman jonas_lists at frukt.org
Fri Mar 16 07:40:02 EDT 2007

Dirk the Daring wrote:

>     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

Note that that's a SHOULD and not a MUST.

I haven't read the complete RFC recently but nothing you quoted
requires the address in HELO/EHLO to be a IP literal or a FQDN.

You and your server can of course still implement that
requirement if you want to. Just don't refer to the RFC if
someone complains (unless you left out things in the RFC
supporting your position).

Jonas Eckerman, FSDB & Fruktträdet

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