On Thu, Jun 24, 2004 at 09:38:32PM +0100, Roy Badami wrote:
|
| No, an SRV lookup on the HELO (then an A lookup on the result of that).
|
| I think it works like an SPF record containing a single 'a' mechanism.
|
| Normally you'd be expected to have something like:
|
| mx-1.isp.com. IN A 1.1.1.1
| mx-2.isp.com. IN A 2.2.2.2
| mx-3.isp.com. IN A 3.3.3.3
|
| _client._smtp.mx-1.isp.com. IN SRV 1 2 mx-1.isp.com.
| _client._smtp.mx-2.isp.com. IN SRV 1 2 mx-2.isp.com.
| _client._smtp.mx-3.isp.com. IN SRV 1 2 mx-3.isp.com.
If this is true, then CSV is logically equivalent to a block
record, and my comments about factored records are not
relevant.
More relevant is my suggestion that doing an SPF lookup
against the HELO name can offer the same semantics.
Which one is more lightweight becomes a question of whether
you already have an SPF library at hand :)