Re: Connections with bad DNS cause lockups

[Gleb Paharenko]

Hello.


> is that when it gets probed, it COMPLETELY offlines (DOS) the server.

One upon a time I solved such an issue with MySQL on FreeBSD by switching
to the official binaries from:
  http://dev.mysql.com/downloads

Still, the recommended way to run MySQL on FreeBSD is compiling it from the ports. 


> Hi,
> 
> 
>        Thanks for the reply.  I did see that page before, but
> I guess my bigger question is why if the DNS is broken/slow, why
> does the entire server come to a COMPLETE halt, no commands can
> be done via either TCP *OR* the socket.  If it just errored, that
> session took forever, whatever... I could understand. The problem
> is that when it gets probed, it COMPLETELY offlines (DOS) the server.
> And just *1* connection!
> 
>        Just also seems difficult to keep proper documentation if
> we are using IPs and not complete hostnames.
> 
> 
>                Thanks, Tuc
>> 
>> Tuc at T-B-O-H <ml@stripped> wrote:
>> > Hi,
>> > 
>> >        We seem to be running into a problem with our 
>> > installation that we don't understand.
>> > 
>> >        We are running "mysql-server-4.0.25" from
>> > the ports collection on a FreeBSD 5.3-RELEASE-p10
>> > machine. Its tcpwrapper'd to only allow from our
>> > /24, and a single machine outside the /24.
>> > 
>> >        At times, all of a sudden the server seems
>> > to "freeze". It appears that we've narrowed it down
>> > to an issue with people attacking the server that
>> > come from a site that has a bad reverse DNS setup.
>> > 
>> >        Has anyone else seen this, or knows how
>> > to stop it?
>> > 
>> >                Thanks, Tuc
>> > 
>> 
>> 
>> 

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