[120326] in North American Network Operators' Group
Re: Arrogant RBL list maintainers
daemon@ATHENA.MIT.EDU (Matthew Petach)
Wed Dec 16 12:22:39 2009
In-Reply-To: <813.1260969676@localhost>
Date: Wed, 16 Dec 2009 09:21:42 -0800
From: Matthew Petach <mpetach@netflight.com>
To: Valdis.Kletnieks@vt.edu
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Wed, Dec 16, 2009 at 5:21 AM, <Valdis.Kletnieks@vt.edu> wrote:
> On Wed, 16 Dec 2009 07:06:55 EST, Mike Lieman said:
>
>> What's the word for 'mail server' in Lower Sorbian, and does your algori=
thm
>> properly detect it in a hostname? =A0See the problem here?
>
> When the hostname at that IP address is exactly one incremented character
> different than the preceding address, and one decremented character diffe=
rent
> than the following address, and that pattern holds across a /24, they're
> probably not mail servers. =A0Nobody has 256 'frzzmabs-1'..'frzzzmabs-256=
'
> servers in the same /24 =A0for *anything* user-facing.
>
You clearly haven't set up webmail farms to handle half a billion accounts
before. ^_^;
We name our (many thousands of) webmail front end boxes as
webXYYZZ.mail.$site.yahoo.com, so for cluster 3, farm 57, you
end up with a string of hosts all in a row like
web35701.mail.mud.yahoo.com
web35702.mail.mud.yahoo.com
web35703.mail.mud.yahoo.com
web35704.mail.mud.yahoo.com
web35705.mail.mud.yahoo.com
web35706.mail.mud.yahoo.com
web35707.mail.mud.yahoo.com
web35708.mail.mud.yahoo.com
...etc...
Take a look at the reverse DNS for the entire 66.163.178.0/23 subnet;
you'll find that when you're doing things at large scale, you can't really
get away from having sequentially numbered reverse DNS entries all
in a row, exactly as you seem to think "Nobody has". :/
Matt
