nanog mailing list archives

Re: Anti-spam System Idea


From: Niels Bakker <niels=nanog () bakker net>
Date: Mon, 16 Feb 2004 17:08:39 +0100


* baldwinL () mynetwatchman com (Lawrence Baldwin) [Mon 16 Feb 2004, 16:17 CET]:
DHCP, though technically dynamic addressing is far less of a problem as
IP address do NOT typically change very often...remember DHCP leases
are renewed automatically by the client when the lease is 50% to
expiration.
Many DHCP clients also cache their previously leased IP (e.g. Windows)
and explicitly request the same IP even across lease expirations...
depending on the service provider, DHCP clients often maintain the same
IP for months at a time (aka "sticky IP").  Some PPPoE gateways also
maintain username to IP caches so sticky IPs can also result in that
scenario as well.

Some ISPs configure their systems to hand out different IP addresses,
to discourage people from running servers (they'd have to update
www.theirdomain.tld each time their address would change).  This
practice gave dynamic dns services the opportunity to fill a need with
consumers.


        -- Niels.

-- 
Blessed are the Watchmakers, for they shall inherit the earth.


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