[ietf-dkim] Underscore considerations

[Steve Atkins]

On Jun 9, 2006, at 8:25 AM, Eliot Lear wrote:

> Steve Atkins wrote:
>>
>> No, *host names* are scarcely restricted at all. You may wish it were
>> otherwise, but it's not the case. In particular, underscores are
>> downright common in hostnames, and most DNS servers don't put any
>> constraints on them. There are RFC requirements on them, sure, but
>> most people naming hosts aren't aware of them, they're not  
>> enforced by
>> software and nothing bad happens when you violate them.
>>
>> About the only thing you can rely on is that most (all?) registries
>> enforce those character restrictions in domains registered with them.
>> Which, fortunately, is enough to avoid the _domainkey.com "problem".
>
> People do all sorts of dumb things.  Shall we document them all?

No. But nor shall we rely on them not doing them as reason to dismiss
a supposed "security" issue. I can think of dozens of other reasons to
do so, but "people don't put underscores in hostnames" isn't one.

Cheers,
   Steve