SRV lookup support (Bugzilla 2217)

[John-Mark Gurney]

Thorsten Glaser wrote this message on Thu, Feb 18, 2021 at 20:28 +0100:
> On Thu, 18 Feb 2021, James Bottomley wrote:
> 
> > > It???s still a level of indirection that isn???t traditionally used, and
> 						 ^^^^^^^^^^^^
> 
> > SRV is used as a requirement by several protocols today.  Xmpp simply
> 						    ^^^^^
> 
> Do you see it?

SRV records were defined in RFC2782, Feb 2000.

SIP has been documented to use SRV records since June 2002:
https://tools.ietf.org/html/rfc3263

XMPP has perfered using SRV since 2011 (RFC6120):
https://tools.ietf.org/html/rfc6120#section-3.2.1

Just because **YOU** don't use it, doesn't mean that it isn't in wide
deployment and use.

I've been using SRV records for over 10 years now on my own domain:
date: 2010/11/12 04:12:47;  author: jmg;  state: Exp;  lines: +2 -2
fix SRV record.. required to point to an A record...

and I've never had any issues with it either...  It just works...

as you can tell my initial setup didn't work, but this was a fix
to a commit from 4 minutes earlier when I initially set it up..

> > >  especially considering name resolution is not just DNS (think
> > > /etc/hosts for example).
> > 
> > /etc/host only resolves A and AAAA records, so it would have no impact
> > on SRV records at all.
> 
> That???s part of what makes me nervous. If foo.example.com has an SRV RR
> and I add an entry for foo.example.com into /etc/hosts to temporarily
> locally redirect it, does that mean the hosts entry will be ignored if
> SRV RR usage is enabled?
> 
> I can???t see where this will end up in anything other than sysadmin
> tears.

This is where ssh -v should be explicit and clear where it's getting
the IP address and where it's connecting.  If you're system is poorly
configured, then yes, there will be issues w/ it, and option need to be
available to detect it, and fix them as well.

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."