out of place mx records.

[Matus UHLAR - fantomas]

> In message <20101112135657.GB22735 at fantomas.sk>, Matus UHLAR - fantomas writes:
> > On 29.10.10 12:49, Mark Andrews wrote:
> > > And they can do a SMTP level rejection rather than waiting for the
> > > sending server to abandon sending the email due to multiple timeouts.
> > > Just return 550 for all mail directed to users at those hosts.   It
> > > would be nice if we could standardise a MX target of "." as saying
> > > that this domain doesn't accept email e.g. "MX 0 ." the same way
> > > as "SRV 0 0 0 ." means that there is no service for the named
> > > protocol.  That way the sending MTA or the MSA can reject the email.
> > > 
> > > Every time it get suggested people shoot it down worrying about
> > > private nets that have addresses at "." or get worried about thousands
> > > of machines making A/AAAA queries for "." where the MTA doesn't
> > > check that the MX target is a valid host name.
> > 
> > the same would apply for any other hostname not recognized by mailservers.
> > Even localhost, if some servers do not contain zone for it.
> > 
> > Technically the best solution would be dropping fallback for A address,
> > however it's apparently unapplicable (or would take years).
> > 
> > BTW.
> > 
> > I was told that "." is not a valid hostname and that it causes DNSSEC
> > problems, at least with debian's named (9.6 ESV now, 9.5.1 before)
> > ... can you confirm this?

On 13.11.10 01:24, Mark Andrews wrote:
> "." isn't a valid hostname but named will accept it as a place holder.
> 
> % named-checkzone example test
> test:1: no TTL specified; using SOA MINTTL instead
> zone example/IN: example/MX '.' (out of zone) has no addresses records (A or AAAA)
> zone example/IN: loaded serial 0
> OK
> % cat test
> @ IN SOA . . 0 0 0 0 0
> @ IN NS .
> @ IN MX 10 .
> % 
> 
> It's easy enough to remove the address checks for ".".

what about check-mx setting, can it be also affected by this setting?

> DNSSEC doesn't care about valid hostnames.

ok

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