[AusNOG] Speaking of DNS...

[Mark Foster]

Thanks to everyone who provided some useful responses.
The bleating about off-topic, I agree, is more off-topic than this is.  
The NOG is useful because it has a 'critical mass' of people who run 
networks - as someone posted earlier, try to make your interwebs work 
without DNS and see how far you go?

Geordie's post below is also correct in that tools such as 
whatsmydns.net are a very high level tool.  Clearly with the closure of 
open resolvers there's going to need to be some cooperation amongst 
network operators and their support staff in providing troubleshooting 
assistance if DNS things go pear-shaped in the future, but if you can 
narrow it down to a subset of particular networks, you should probably 
engage them directly before opting for a 'scattergun' approach to a 
mailing list or similar.

This of course also means that support teams need to be prepared to 
provide technical support without the 'sorry, you havn't given me a 
valid username, so you're not my customer, goodbye' that I have 
experienced before. :/

Cheers
Mark.


On 13/02/2014 1:21 p.m., Geordie Guy wrote:
> It is indeed a simple and useful tool but it only gives a 10000 ft 
> overview of what's going on.  Tools like that get a collection of 
> servers (or routers with IP dns-server command run on them for the 
> coterie of NOGgers who insist that any post that doesn't include three 
> AS numbers and a traceroute is off topic and layers five through seven 
> of the OSI Reference Model are some sort of New Testament heresy), one 
> per country or continent, and shows you what IP they resolve for a 
> given fqdn.  As network operators we know that's a fairly blunt 
> instrument.  Yesterday's drama for us showed that the primary problem 
> we had in the wake of the whoopsie was that Telstra's DNS 
> infrastructure for enterprise and business seems to have a shorter TTL 
> or caching lifetimes on those IP records than the Bigpond side of 
> their business does, that smaller partners and customers of ours might 
> use.  This allowed us to figure out where it was working and where it 
> wasn't, but as far as WhatsmyDNS was concerned all of Australia 
> (represented by a single DNS server) was ok.
>
> So yeah, if you're the type of wag who unveils a new business service 
> by changing a DNS record, whatsmyDNS will give you an idea of the 
> geographies that you can probably expect your service to be live in 
> and who is still getting the coming soon page with the animated gifs 
> of the construction signs, but if you've got a local problem with 
> different Australian networks having different results then you need 
> looking glasses or a community of operators who can give you their 
> view of the world.
>
>
>
> On Thu, Feb 13, 2014 at 10:38 AM, Nathan Phelan 
> <nathan at interconnekt.com.au <mailto:nathan at interconnekt.com.au>> wrote:
>
>     Nice one Mark!
>
>     https://www.whatsmydns.net/ is a simple dns tool too.
>
>     Cheers,
>     Nathan
>
>     -----Original Message-----
>     From: AusNOG [mailto:ausnog-bounces at lists.ausnog.net
>     <mailto:ausnog-bounces at lists.ausnog.net>] On Behalf Of Nishal
>     Goburdhan
>     Sent: Wednesday, 12 February 2014 8:45 PM
>     To: Mark Foster
>     Cc: ausnog at lists.ausnog.net <mailto:ausnog at lists.ausnog.net>
>     Subject: Re: [AusNOG] Speaking of DNS...
>
>
>     On 12 Feb 2014, at 9:23 AM, Mark Foster <blakjak at blakjak.net
>     <mailto:blakjak at blakjak.net>> wrote:
>
>     > ... what's the done method of troubleshooting DNS problems that
>     only affect certain network(s), now that open resolvers are
>     (hopefully) a thing of the past?
>     > I have semi-regularly struggled with troubleshooting email
>     delivery problems (for example), due to an inability to see what
>     ISP X sees as my MX record.
>     >
>     > Onceuponatime I could just query their DNS servers myself. Now
>     it seems I either have to hope that their helpdesk understand what
>     an MX record actually is, or try to find a shell account on a
>     machine within their network to tinker with...
>     >
>     > I didn't realise that DNS was something that was a candidate for
>     a network of 'looking-glass' systems, but perhaps it is... Need a
>     nice, rate-limited, hard-to-abuse web-based DNS lookup tool to
>     become commonly available, perhaps?
>
>
>     http://www.bortzmeyer.org/dns-lg.html
>
>
>     --n.
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