The End-To-End Internet (was Re: Blocking MX query)

valdis.kletnieks at valdis.kletnieks at
Fri Sep 7 03:44:05 UTC 2012

On Fri, 07 Sep 2012 08:30:12 +1000, Mark Andrews said:
> In message <85250.1346959671 at>, valdis.kletnieks at writes:
> > My PS3 may want to talk to the world, but I have no control over Comcast's DNS.
> What point are you trying to make?  Comcast's servers support SRV as do all
> general purpose name servers.  For HTTP at least you need to be backwards
> compatible so there is no reason not to add SRV support.

Sure, Comcast's servers will happily support an SRV entry for my PS3.

However, Comcast's business processes don't support a way for me to request
said SRV record be listed.  Heck, I don't even get a static IP with my current service
package. ;)

Now *I* have the technical chops to talk to the guys at or other
providers and get an SRV entry created under some domain name pointing back at
my IP address.  However, Joe Sixpack doesn't really have that option.  And
unless you figure out a scalable and universal way for Joe Sixpack's Xbox or PS3 or
whatever to request an SRV entry saying that the PS3 wants to do service
"foobar" on port 34823, you can't use SRV like that.

A better proposal would probably be having the NAT itself run a 'portmap' type service
on a well known port like 111.  Except that still doesn't do a very good job of
disambiguating two instances of "foobar" behind a NAT...

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