Thoughts on best practice for naming router infrastructure in DNS

Fri Jun 29 12:39:59 UTC 2007

On Friday 15 June 2007 00:27, Olsen, Jason wrote:

> So, what practices do you folks follow?  What are the up
> and downsides you encounter?

At my previous employer, we came up with a formula that we 
were happy with. For reverse DNS, it involves:

* defining the interface
* defining the device function
* defining the local location
* defining the international location

o device interface could be:

	fa-0-0-0
	gi-1-0-0
	s0-0-0
	pos-1-0
	tun0

  this also takes subinterfaces into account; for cases where
  we've had to classify a switch VI the "routes" IP traffic:

	vlan100

o device function could be:

	br-gw (border router)
	cr-gw (core router)
	cr-sw (core switch)
	edge-gw (edge router)
	edge-sw (edge switch)

o device local location; we normally define this using the
  IATA 3-letter international city/airport code:

	LAX (Los Angeles
	ABV (Abuja)
	DXB (Dubai)
	CPH (Copenhagen)
	MEL (Melbourne)
	HKG (Hong Kong)

  it is not uncommon to have towns or cities being
  abbreviated by the locals in some other way, either
  because they do not care for the IATA code :-), or if
  they do, are not included in the IATA database; in this
  case, you may use your imagination; for us, depending on
  the length of the name, we spell out the full town's name.

o device international location is easily defined if your TLD
  is based on a country, e.g., .uk, .ae, .ke, .za, .na, e.t.c.
  for situations where your domain name would end in a
  non-region specific TLD, e.g., .com, .net, .org, e.t.c., one
  would prefix a state or country (in the case of a global
  network) to the domain name, e.g.:

	.uk.somelargenetwork.com
	.za.somelargenetwork.com

  things could get interesting if you setup multiple PoP's in
  another location that would still fall under your .com or
  other such TLD, but there are ways to fix that :-).

So, a final example of, say, core router number 5 and edge 
switch number 3 located in a datacentre of a local Australian 
ISP in Melbourne:

gi-0-0-1.cr-gw-5-mel.somenetworknetwork.com.au
vlan876.edge-sw-3-mel.somenetwork.com.au

Say a large network, whose home network was the US, decided to 
setup a single PoP in Johannesburg that included one core 
router and one border router, but whose domain name ended 
in .net, it would look something like this:

pos-3-0.cr-gw-1-jnb.za.somelargenetwork.net
gi-0-0-1.br-gw-1-jnb.za.somelargenetwork.net

You could then use the script Joe Abley kindly posted earlier 
to automatically generate your entries.

Of course, this was our own approach. Different folks have 
different strokes.

Hope this helps.

Cheers,

Mark.