what the heck do i do now?

Tue Feb 6 06:31:45 UTC 2007

On Feb 6, 2007, at 12:40 AM, Jeremy Chadwick wrote:

>
> On Mon, Feb 05, 2007 at 10:13:08PM -0500, Jon Lewis wrote:
>> On Mon, 5 Feb 2007, Jeremy Chadwick wrote:
>>> 1) DNS servers which are not configured to blackhole IANA-reserved
>>>  network blocks (read: the majority) will blindly try to reach
>>>  192.0.0.0/17 and friends.
>>
>>    192.0.2.0/24 - This block is assigned as "TEST-NET" for use in
>>    documentation and example code.  It is often used in  
>> conjunction with
>>    domain names example.com or example.net in vendor and protocol
>>    documentation.  Addresses within this block should not appear  
>> on the
>>    public Internet.
>
> I was going purely off of what ARIN reports:
>
> Internet Assigned Numbers Authority RESERVED-192 (NET-192-0-0-0-1)
>                                   192.0.0.0 - 192.0.127.255
> Internet Assigned Numbers Authority IANA (NET-192-0-2-0-1)
>                                   192.0.2.0 - 192.0.2.255
>
> If there is something magical about 192.0.2.0/24, then I'd love to
> know what it is (please do educate me!).  But from my perspective, it
> just looks like another IANA-reserved netblock.

RFC 3330

    192.0.2.0/24 - This block is assigned as "TEST-NET" for use in
    documentation and example code.  It is often used in conjunction  
with
    domain names example.com or example.net in vendor and protocol
    documentation.  Addresses within this block should not appear on the
    public Internet.

BTW - there's nothing that says anything about filtering  
192.0.0.0/17.  It might be reserved for IANA, but there's nothing  
saying it can't be used.   Looks to me like ICANN is using some of  
their sub-allocation in that space.

>
>> That /24 doesn't show up in BGP unless something is broken or you  
>> have a
>> cymru bogon feed.  Either way, worst case is you're default  
>> routing to an
>> ISP/NSP and the packets get a few hops before someone drops them as
>> unroutable.
>
> Right, so the mentality here is that "someone" will eventually
> filter the packets or they'll be dropped due to a null route
> BGP rule.  This I understand, but IMHO it's better to filter such
> packets before they ever reach someone else's networking gear.
> (Sorry if I'm not phrasing this as eloquently as possible.)  In my
> case, I simply purchase co-lo space from providers and rely on their
> routing configurations, hoping they're doing things properly.  But
> as one can see from the ipfw stats I pasted, some aren't.  Understand
> where I'm coming from?

Packets destined for 192.0.2.0/24 will follow the money trail.  As  
soon as someone stops paying, the packets will die.  (Actually  
sometimes they'll drop off sooner than the money trail, but that's  
irrelevant).  What I'm saying is that by sending packets to 192.0.2.0  
the only people who'll be "harmed" by that action are people you're  
paying.

>
>>> 2) Some people (like myself) have ipfw/pf rules which block and
>>>  log outbound packets to reserved blocks.  We log these because
>>>  usually it's the sign of broken software or possibly some weird
>>>  IP routing (read: OS IP stack) problem.  In the case of ipfw (I
>>>  haven't tested pf), the block gets reported to underlying layers
>>>  as EACCES, which can be incredibly confusing for admins.
>>
>> If it means they get noticed, mission accomplished.  That's  
>> exactly what
>> Paul wants.
>
> In that case, it's a win-win situation.

Which is probably why it was suggested....

>
>>> My vote is to simply remove the NS and A records for maps.vix.com
>>> and let people utilise search engines and mailing list archives to
>>> figure out where to go (mail-abuse).
>>
>> The vix.com NS's will get slammed with all the DNSBL queries then.
>> The suggestions I made at least get some of the queriers (assuming  
>> they
>> have properly functioning caches) off your back for a while.
>
> Hmm, yes, you're absolutely correct.  But I'm curious why you picked
> 192.0.2.0/24 rather than some other reserved block?  (I've also sent
> a copy of this discussion to an associate of mine at Nominum, who's
> now wondering the same thing I am...)

Pointing to RFC 1918 space is likely to cause "harm".  192.0.2.0/24  
is guaranteed not to (unless people don't follow RFC allocations....)

>
> I've found this thread immensely educational so far!
>
> -- 
> | Jeremy Chadwick                                 jdc at  
> parodius.com |
> | Parodius Networking                        http:// 
> www.parodius.com/ |
> | UNIX Systems Administrator                   Mountain View, CA,  
> USA |
> | Making life hard for others since 1977.               PGP:  
> 4BD6C0CB |
>