On Wed, Dec 16, 2009 at 5:21 AM, <[email protected]> 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 algorithm >> properly detect it in a hostname? See the problem here? > > When the hostname at that IP address is exactly one incremented character > different than the preceding address, and one decremented character different > than the following address, and that pattern holds across a /24, they're > probably not mail servers. Nobody has 256 'frzzmabs-1'..'frzzzmabs-256' > servers in the same /24 for *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
