Re: disable dnsserver - what is the cost?

Timur Tabi writes:

>On Tue, 17 Nov 1998, Henrik Nordstrom wrote:
>
>>Timur Tabi wrote:
>>>
>>> When I disable DNS support (i.e. don't let squid run
>>> dnsserver), I get a warning that performance could be
>>> very poor. Could someone explain, in layman's terms,
>>> exactly how performance could be poor?
>>
>>If one user requests a host where a blocking DNS lookup is
>>required,
>
>Can you give me an example of a blocking DNS lookup?

Strictly speaking, all DNS lookups "block" the process. Some
lookups take longer than others. These seem to take a particularly
long time for me:

        banners.worldnetgaming.com
        alex95.gang4d.ml.org

So if you request a URL with these hostnames, Squid is
stuck until the DNS lookup returns or times out. If you change
your mind and abort the request and make another request, you
will get nothing from Squid until the previous lookup times out.
Could take up to two minutes.

>>then Squid is completely blocked until this DNS
>>lookup finishes which can be up to a minute. During this
>>time no traffic at all passes Squid and the users may
>>think that the Internet (or the proxy) is dead.
>
>So as long as it appears to work normally, then I can assume
>that the lack of dnsserver is not a problem.

If it doesn't bother you, then its probably fine.

Duane W.
Received on Tue Nov 17 1998 - 17:09:53 MST