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Re: weird dns error resolving "www"
From: Len Conrad
Date: Saturday, September 22, 2001
Time: 4:04:57 pm
>yeah, well "ns2" is out of commission because of the WTC
>bombing...ns.idt.net is only a secondary.
there no such thing as "only a secondary". To internet, all delegated=20
NS's are to answer authoritatively.
>..does DNS Expert's info indicate
>it doesn't hold the zone data, or it's just "nonauthoritative"?
it's answering but without authority.
>Also, if the primary NS _is_ responding, why would it make the resolutio=
n
>any slower if one of the NS's in non-operational?
If the dead NS is queried first, then the resolver will timeout and then=20
try the next. BIND actually queries all NS's and chooses the fastest on=
e,=20
with lowest RTT, round-trip time.
>Lastly, why is it more desirable to have 2 A records pointing to an IP
>instead of an A record and a CNAME?
because CNAME's require a second query to retrieve the canonical's A=20
record, but more importanlty, CNAME's have rules that many people screw=20
up, which breaks their zone (loss of authority).
ime, CNAME's seem to be a useless "knob to twist", ie, "oh, I haven=B4t=20
twisted any CNAME knobs yet, I better put some in my zone, "just because =
I=20
can" " :))
btw, your www response pb's might be due not to DNS slow/not responding b=
ut=20
the www server or it's last-hop internet link being overwhelmed with nimd=
a=20
crap http requests, so that the web server isn't responding at all or=20
extremely slowly so that the browsers time out.
Len
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