[156122] in North American Network Operators' Group
Re: The End-To-End Internet (was Re: Blocking MX query)
daemon@ATHENA.MIT.EDU (Sean Harlow)
Fri Sep 7 01:32:47 2012
From: Sean Harlow <sean@seanharlow.info>
In-Reply-To: <108454.1346989445@turing-police.cc.vt.edu>
Date: Fri, 7 Sep 2012 01:31:51 -0400
To: Valdis.Kletnieks@vt.edu
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Sep 6, 2012, at 23:44, Valdis.Kletnieks@vt.edu wrote:
> 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.
I think you missed the point on this one. Even if your PS3 has a public =
IP with no limitations on ports, how exactly are others going to find it =
to connect to it?
I see three options here:
1. You have to give them the IP address, in which case it's not exactly =
rocket science to give them the port as well. The same Joe Sixpack who =
couldn't find the port couldn't likely figure out his IP either, so the =
PS3 would have to be able to identify its own public-facing IP and tell =
him, in which case it could also tell him the port.
2. DNS, which while many don't have this ability any that do should have =
no problem setting a SRV record. Obviously not all clients support the =
use of SRV records, but that's not the subject of this particular =
tangent.
3. Intermediary directory server hosted at a known location. Pretty =
much the standard solution for actual PS3 titles as well as almost all =
other games since the late '90s. Rather than telling the user, the PS3 =
tells the central server its IP and port plus any useful metadata about =
the service being offered and the user just needs to give his friend a =
name or other identifier to find it in the list.=20
None of these options are impacted by being behind a NAT as long as they =
have the ability to open a port via UPnP or equivalent, so if in an =
ideal world all client software understood SRV records this particular =
negative of NAT would be of minimal impact. Of course the real world is =
nowhere close to ideal and personally SIP phones and Jabber clients are =
the only things I've ever observed widely using SRV records, so at least =
for now I can't just do something like "_http._tcp.seanharlow.info 86400 =
IN SRV 0 5 8080 my.home.fake." and host my personal site on my home =
server (Mozilla has had a bug open on this for over ten years, Chrome =
for three, and Webkit closed their bug as WONTFIX two years ago so I =
don't expect this to change any time soon). At this point we're coming =
back around to the already raised point about if we're going to have to =
change a lot of things, why not just put that effort in to doing it =
right with IPv6 rather than trying to keep address conservation via DNAT =
alive?
---
Sean Harlow
sean@seanharlow.info=
