North American Network Operators Group
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Re: Memory leak cause of Comcast DNS problems

  • From: Florian Weimer
  • Date: Sun Apr 17 12:30:48 2005 
* Sean Donelan:

> Perhaps your DNS software also has a memory leak?  Anyone know which
> software Comcast was using?  Should other ISPs be concerned they might
> have the same latent problem in their systems?

Probably yes, especially if they don't read documentation of their DNS
software.

| The maximum amount of memory to use for the server's cache, in
| bytes. [...] The default is unlimited, meaning that records are
| purged from the cache only when their TTLs expire.

The number of complaints I've heard that "DNS resolvers eat *so* much
memory" suggests that few people tweak the default configuration. 8-(

However, it's unlikely that this was the cause of Comcast's problems
because DNS cache overflows would have an impact on a much larger
scale.