Re: [cobalt-users] RaQ4 performance: slow first page load

[flash22@xxxxxxx]

On Sat, 14 Jul 2001, Edward Bishop wrote:

> how do I ascertain whether all the NS
> records are working?

ok, microfaq ;)

First, lookup the root server data with whois...
ie: using cobalt's domain name as an example

whois cobalt.com
   Domain Name: COBALT.COM
   Registrar: NETWORK SOLUTIONS, INC.
   Whois Server: whois.networksolutions.com
   Referral URL: http://www.networksolutions.com
   Name Server: NS1.COBALT.COM
   Name Server: NS2.COBALT.COM

Now you know the names of the nameservers that are *supposed* to answer
for the domain, what you want to check is that they are in fact doing
so...

use nslookup (you can also use dig) to ask each nameserver for the answer,
and also make sure they know about each other via the NS records in the
information they return...


 nslookup
Default Server:  nano
Address:  0.0.0.0

> set type=any
> server NS1.COBALT.COM
Default Server:  NS1.COBALT.COM
Address:  63.77.128.10

This says 'return info about 'any' type of record, and ask ns1.cobalt.com
specificly for the answer (and noone else)

Next we ask for the zone by simply typeing it in...

> cobalt.com
Server:  NS1.COBALT.COM
Address:  63.77.128.10

cobalt.com      preference = 30, mail exchanger = mail.cobalt.com
cobalt.com      internet address = 63.77.128.51
cobalt.com      nameserver = ns1.cobalt.com
cobalt.com      nameserver = ns2.cobalt.com
[etc etc]
mail.cobalt.com internet address = 63.77.128.166
ns1.cobalt.com  internet address = 63.77.128.10
ns2.cobalt.com  internet address = 63.77.128.11


Note that the 2 nameservers are listed again here, this is important, the
zone has to list the same  nameservers the root (whois) data did, also
the IP addresses should match....and there shouldn't be 'extra' ns
records, tho there will likely be other data here...

Then check the other server...

> server ns2.cobalt.com

and repeat (cobalt.com) to see of the data returned *matches* what the
other nameserver gave....

If you get delays, errors, or the IP addresses don't match across
nameservers , then you have things to fix :)

You can also check the mapping from IP address to name, tho there are some
complications here, the nameservers that answer those questions are not
the same ones that answer the domain name in most cases

To lookup a IP address you also have to reverse it, andd add in-addr.arpa
to the end, ie:

51.128.77.63.in-addr.arpa
Server:  ns1.cobalt.com
Address:  63.77.128.10

51.128.77.63.in-addr.arpa       name = www.cobalt.com
128.77.63.in-addr.arpa  nameserver = ns1.cobalt.com
ns1.cobalt.com  internet address = 63.77.128.10

In this particular case, this nameserver happens to be the one that knows
the answer...

In any case, if you get an answer at all, it';s good if it matches
properly, tho some isp's may insist on returning their own domain name
instead of yours...(Which is still better than nothing at all)

(rerun nslookup, and skip the 'server=' command to use the default
nameserver when doing this )

ps: ok, it's a microfaq, there are gobs of things beyond this ;)

 gsh