Security Advisory: Server Lockup Upon IXFR or DDNS Update Combined with High Query Rate

[David Coulthart]

On Feb 22, 2011, at 3:55 PM, Larissa Shapiro wrote:
> Description and Impact:
> 
> When an authoritative server processes a successful IXFR transfer or a dynamic update, there is a small window of time during which the IXFR/update coupled with a query may cause a deadlock to occur. This deadlock will cause the server to stop processing all requests. A high query rate and/or a high update rate will increase the probability of this condition.

Does the "authoritative server that processes an IXFR transfer" refer to:

a) the IXFR server?
b) the IXFR client?
c) both?

Thanks,
Dave Coulthart