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At 5:24 PM -0500 3/9/2000, Clarence Kwei wrote:
Re: Honest Base Config
From: Men & Mice Support
Date: Thursday, March 9, 2000
Time: 11:54:00 pm
>on 3/9/00 4:30 PM, Jerry Pasker-Systems Admin. at info@n-connect.net wrote:
>
>>> That's just plain not true. I run my primary DNS on a Power Mac 6100 with
>>> 40 megs ram and it takes over 2 million queries per month. My secondary
>>> server is on a Quadra 600 with 28 megs ram.
>>>
>>> Primary is ns1.ninewire.com
>>> Secondary is ns2.ninewire.com
>>>
>>> Feel free to test the speed but they seem quick to me.
>>>
>>
>> 2 million per month averages to 66,000 queries per day. This server would
>> need to do several times as many queries per day. Even if it only did
>> ~180,000 per day, for the 500,000 hits, that's still a lot of lookups.
>> Besides, I've noticed that DNS querries (like mail, and web hits) may be
>> slow to moderate during part of the day, and then really spike during the
>> 'busy' times of the day.
>
>Maybe I'm not fully understanding DNS traffic... please let me know if I'm
>off-base with this...
>
>I thought that every time a user visits your site, your DNS server gets
>queried for information. That happens only once per unique visitor since
>after the first successful query, the information is pretty much set for the
>entire session - that is future hits from the user during the session do not
>need repeated DNS queries.
Not exactly. If two users of a given DNS resolver, such as two users of an ISP, visit your site, your DNS server is only queried once for "www.domain.com". The DNS server caches that value for TTL seconds.
>That's one part of DNS traffic, the other part is SOA information, which I
>really don't have a clue how it works. Do the main DNS servers hit your DNS
>server according to the refresh value in your SOA record? Is it the
>Expiration or the TTL value?
>
>If anyone can shed some light on this, I would greatly appreciate it.
>Thanks.
OK, here's what they mean:
Serial: A number that is increased with every change to the domain file. It is used by the secondary servers to determine if they need to request a new copy of the domain from the primary server.
Refresh: The frequency (in seconds) at which the secondary server(s) attempt to check the primary server for an updated version of the domain.
Retry: If the refresh attempt fails, a secondary server will try again this many seconds later.
Expire: If repeated refresh attempts fail, despite retrying, a secondary server will stop serving the domain after this many seconds, with the idea that its cached version is probably out of date.
Minimum: The default TTL of all records in the domain. Each record can have its own individual TTL, however, which overrides this default.
TTL: "Time To Live". This is the length of time in seconds that a resolver (someone else's DNS server) should cache this record. While the record is cached, requests that the resolver receives for this record will not result in a DNS query of your servers. The TTL in the Domain Information dialog is the TTL of the SOA (Start Of Authority) record.
____________________________________________________________________
Chris Buxton cbuxton@menandmice.com
Men & Mice http://www.menandmice.com
Makers of: QuickDNS Pro
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