Re: Questions on Squid (dnsserver) and DNS

1a. Hmm. I don't see anything on that page directly related to DNS
performance. Are you referring to the patch that enables dnsserver to
return TTL values? There's also the advice to have ones nameserver on
the same subnet, but I'm already doing that.

1b. I understand that it is not advised to run the nameserver and
Squid on the same machine. Nevertheless, that is the situation I have
to work with.

2. So I can assume that dnsserver is almost always querying my local
nameserver in preference to my ISPs servers? Good. I expect that the
desired IP address will often be found in BIND's cache.

3. The reconfiguring of Squid is related to DNS performance in that
dnsserver will cache n IP numbers (1024 by default?) By reloading all
the copies of dnsserver, that cached info is lost and must be regained
in subsequent lookups by Squid.

Thanks for the response.

On Fri, 3 Dec 1999 02:50:29 +0500, Ahsan Khan wrote:
>Dear Steve,
>
> Great Questions,,
>
>1:- As well as BIND and Squid Dnsserver is concern, Squid has an option
>to comple with your bind for optimum performance, see
>http://squid.nlanr.net/FAQ and more over if i will be on your place, i would
>rather made a cache only DNS for My squid system so i got less time for DNS.
>
>2:- Always Remmeber In resolve.conf Your DNS and every other thing will look
>for First IP for DNS query and until its fail it will be used for this. If
>its failed then it will try next one, you can increase or decrease the
>timeout by recompiling the dns with proper modifications.
>
>3:- By resonfigureing the squid nothing happen mutch but yes a new
>session of layer in memory waiting for finishing previous requests and
>starting with new config. So i do not think so its related to dns unless u
>will restrat your dns,,
>
>
>With Regards
>Ahsan Khan
>----- Original Message -----
>From: "Steve Snyder" <swsnyder@home.com>
>To: "Squid Mailing List" <squid-users@ircache.net>
>Sent: Friday, December 03, 1999 2:21 AM
>Subject: Questions on Squid (dnsserver) and DNS
>
>
>> I am running Squid (2.2S5) on a Linux box (RedHat v6.0 / kernel
>> v2.2.13) which is also running a nameserver (BIND v8.2.2-P5). Can I
>> get some clarification on Squid's dnsserver vs. BIND?
>>
>> When I cannot resolve a name locally, I (BIND) query one of my ISP's 2
>> nameservers. If that fails, I query a root nameserver. In short, my
>> nameserver is a pretty standard setup.
>>
>> By default, Squid reads these entries from my resolv.conf (the last
>> 2 addresses are also used as forwarders in my BIND configuration):
>>
>> nameserver 127.0.0.1
>> nameserver 111.222.333.444
>> nameserver 555.666.777.888
>>
>> So here, finally, are my questions.
>>
>> 1. Is there an advantage to directing Squid (dnsserver) to use only
>> address 127.0.0.1 for name resolution, or would I just be creating a
>> bottleneck? My thinking is that name resolution would be faster if
>> all resolutions went through the local nameserver, rather than having
>> dnsserver call one of my ISPs nameservers.
>>
>> 2. How frequently does dnsserver query the second or third nameservers
>> read from resolv.conf? Can I assume that because my local nameserver
>> is listed first, that the other server are rarely queried?
>>
>> 3. I reload Squid's dnsserver ("squid -k reconfigure") on a weekly
>> basis in the course of updating my URL redirector. This causes the
>> loss of any IP/name data cached by dnsserver. In contrast, my local
>> nameserver is rarely restarted, so the info it has cached is retained
>> for a longer period. Does this information (relative duration of
>> cached data) affect the optimal relationship between dnsserver and
>> BIND?
>>
>> Thank you.
>>
>>
>> *** Steve Snyder ***
>>
>

*** Steve Snyder ***
Received on Thu Dec 02 1999 - 15:36:02 MST