On 22-Nov-2005, at 20:33, Brendan Murray wrote:

> Stu Fleming  wrote:
>> I have a...friend, let's say...who operates a DNS server at a small
>> ISP.  In a few of the zone files, there are A records that resolve  
>> to IP
>> addresses outside of the Class C that my..friend...controls.  My  
>> friend
>> has been told that this is "against the rules" and that it is  
>> "causing
>> problems".
>
> I suspect I know what's happening here. It was a particular  
> vexation for
> me some time ago when I was responsible for a network, and I'm  
> going to
> guess it's the same one as your ...friend.... is dealing with, and  
> found
> that 3rd parties were registering IP addresses with 'my' Class B as  
> some
> other domain name.

"class B" is also a historical term, and also has no meaning on  
today's Internet.

Perhaps we can save time and also mention that the term "class A" is  
also obsolete.

> i.e I 'control' 172.17.0.0/24 as example.com and someone with a  
> host in my
> range has registered a domain with an external supplier as
> someotherexample.com using 172.17.224.0/24 ip numbers, say.

Right. There is absolutely nothing wrong with this. It's perfectly  
legitimate. You are wasting precious hours of your life by worrying  
about it.

> I looked into it, and asked around, and found that there were no rules
> stopping it, and no technology. I eventually realised that the  
> external
> provider was outside my range of control and had to control my  
> clients by
> telling them that it was against the AUP (as it was)  for them to  
> do it
> this way.

If it's against anybody's AUP, then they have a particularly non- 
enforceable and ludicrous AUP.

>>> Questions:
>> - is resolving an A record outwith the delegated IP range "against  
>> the
>> rules"?
>
> discourteous is about it once they've asked you to stop. But you've  
> got
> paying customers.

Bzzt. There's nothing discourteous about it.

>> - if so, is there any documentation of the rules?
>
> should be against their internal AUP and so its someone elses problem

Bzzt. If it's against their AUP, then their AUP is ridiculous.

>> - what potential problems could this cause to the network that  
>> contains
>> the IP address to which the A records point?
>
> reverse lookups for what you're hosting resolve to their network  
> address
> range. Some mail services might choke

Absolute nonsense. If you have an A record with RDATA which points at  
someone else's device, then mail which follows that A record is  
already broken, since you're sending your mail to someone else.


Joe