North American Network Operators Group

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Re: DNS DOS increasing?

  • From: Miquel van Smoorenburg
  • Date: Mon Jan 21 12:59:57 2002
  • Distribution: cistron
  • Newsgroups: lists.nanog

In article <[email protected]>,
James Smith  <[email protected]> wrote:
>  Get ready for more DOS-like behavior as systems get deployed that have 10
>second TTLs in the DNS. These systems are used to provide multi-isp
>redundancy by pinging each upstreams router, and when a ping fails, start
>giving out a dns response using the other ISP IP range. Same FQDN, new IP.

So what we need is a tunable on the caching DNS server that says

min_allowed_ttl = 300;

if (ttl < min_allowed_ttl) ttl = min_allowed_ttl;

If the above becomes a problem, this will happen.