Slow DNS performance

[Mike Klick]

I have a server that is a SOA for xyz.com (example). It is not actually
hosting xyz.com's site but a host record points to the real DNS server. I am
also using DNS forwarding for everything else.

It's web server host record was www. Recently a "new" record was added.
new.xyz.com. When new is removed access to www is much, much faster. I've
test this several time.

Why does that happen? After repeated attempts keeping news out allow for
normal performance. Both www and new pointed to the same external web
server.

Any ideas?

Mike

( I have restarted DNS server several times too.)

 

[Ace Fekay [MVP]]

In

I have a server that is a SOA for xyz.com (example). It is not
actually hosting xyz.com's site but a host record points to the real
DNS server. I am also using DNS forwarding for everything else.

It's web server host record was www. Recently a "new" record was
added. new.xyz.com. When new is removed access to www is much, much
faster. I've test this several time.

Why does that happen? After repeated attempts keeping news out allow
for normal performance. Both www and new pointed to the same external
web server.

Any ideas?

Mike

( I have restarted DNS server several times too.)

Are the two records, 'new' and 'www' CNAMES? I can understand this happening
if they are.

Why not just create a separate zone called new.xyz.com, and provide the
nameservers on record in the wizard. This way, the resolution will be sent
to the actual nameservers instead of your machine handling it. You can do
the same for www.xyz.com.



--
Regards,
Ace

Please direct all replies ONLY to the Microsoft public newsgroups
so all can benefit.

This posting is provided "AS-IS" with no warranties or guarantees
and confers no rights.

Ace Fekay, MCSE 2003 & 2000, MCSA 2003 & 2000, MCSE+I, MCT, MVP
Microsoft Windows MVP - Windows Server - Directory Services

Security Is Like An Onion, It Has Layers
HAM AND EGGS: A day's work for a chicken;
A lifetime commitment for a pig.

 

[Mike Klick]

Ace:

No, they were just Host records. No CNAME.

So separate zones will help performance issues then?

I have a bunch of networks using forwarding in the same way. That seems
strange to create a new zone for each new one.

Mike

P.S. I don't know if this applies or who to talk to about it but: the
modified HOSTS file from MVPS.ORG. It can drastically slow Win2k Pro's dial
up negotation. I mean it will stay at "registering your computer on the
network" for over a minute. Can you point me to someone who can address this
issue? It is a problem.



"Ace Fekay [MVP]"

 

[Ace Fekay [MVP]]

In

Ace:

No, they were just Host records. No CNAME.

So separate zones will help performance issues then?

I have a bunch of networks using forwarding in the same way. That
seems strange to create a new zone for each new one.

Mike

P.S. I don't know if this applies or who to talk to about it but: the
modified HOSTS file from MVPS.ORG. It can drastically slow Win2k
Pro's dial up negotation. I mean it will stay at "registering your
computer on the network" for over a minute. Can you point me to
someone who can address this issue? It is a problem.

If you have many, then I wouldn't create a zone for each. If you added 'new'
with the same IP as 'www', it wouldn't make sense to slow the system down.

As for the hosts file, the more data in a host file, the slower it will be
pulling that into cache upon intialization. That is a problem, and is the
way the DNS client side resolver and cache service works, and no way to get
around that unless you port it to a DNS server and point the IP to a
non-localhost like 127.0.0.2. Did you say this is on a client machine or on
the DNS server itself?


Ace

 

[Mike Klick]

Hey Ace:

Re: The HOSTS file issue is on the machine itself. A Win2k Pro machine. (I
use the HOSTS file on my XP machine sometimes I dial out when my wireless is
down...I don't notice that behavior. But that Win2k machine for sure. Have
tested it a bunch.)

Re: Other issue. I deleted then put 'new' back several times. Each time it
behaved the same. 'new' slowed things down - or seemingly. Is there a tool
or utility I can use to test and verify this? Maybe, somehow, it is the
provider?!

Thanks,

Mike

"Ace Fekay [MVP]"

 

[Ace Fekay [MVP]]

In

Hey Ace:

Re: The HOSTS file issue is on the machine itself. A Win2k Pro
machine. (I use the HOSTS file on my XP machine sometimes I dial out
when my wireless is down...I don't notice that behavior. But that
Win2k machine for sure. Have tested it a bunch.)

Re: Other issue. I deleted then put 'new' back several times. Each
time it behaved the same. 'new' slowed things down - or seemingly. Is
there a tool or utility I can use to test and verify this? Maybe,
somehow, it is the provider?!

Thanks,

Mike

It doesn't make sense why creating one record on your internal DNS will slow
it down. If you delete both new and www, then just create www, will it work
ok then?


--
Regards,
Ace

Please direct all replies ONLY to the Microsoft public newsgroups
so all can benefit.

This posting is provided "AS-IS" with no warranties or guarantees
and confers no rights.

Ace Fekay, MCSE 2003 & 2000, MCSA 2003 & 2000, MCSE+I, MCT, MVP
Microsoft Windows MVP - Windows Server - Directory Services

Security Is Like An Onion, It Has Layers
HAM AND EGGS: A day's work for a chicken;
A lifetime commitment for a pig.

 

[Mike Klick]

Ace:

I will try deleting both, putting back www, test it, then put back new and
test it.

It is the web page generation that is slow for the ONE web site. All others
are fine. But that one domain is one their server, then hosted externally -
like I said.

I will let you know,

Thanks,

Mike

"Ace Fekay [MVP]"

 

[Ace Fekay [MVP]]

In

Ace:

I will try deleting both, putting back www, test it, then put back
new and test it.

It is the web page generation that is slow for the ONE web site. All
others are fine. But that one domain is one their server, then hosted
externally - like I said.

I will let you know,

Thanks,

Mike

Curious of your results.

Ace

 

[Mike Klick]

Ace:

I tried duplicating it and could not. (This is a school) The adminsitrator
said for weeks their site was creepy crawly slow until I removed 'new'
suddenly all fixed.

I am going to have him try it when they get back with 'new' back on.

Both new and www are pointing to the same IP (like I said) same Mac web
server. Pointing to the same web site too. Wondering if that makes any
difference...

Again I will let you know.

Thanks,

Mike


"Ace Fekay [MVP]"

 

[Ace Fekay [MVP]]

In

Ace:

I tried duplicating it and could not. (This is a school) The
adminsitrator said for weeks their site was creepy crawly slow until
I removed 'new' suddenly all fixed.

I am going to have him try it when they get back with 'new' back on.

Both new and www are pointing to the same IP (like I said) same Mac
web server. Pointing to the same web site too. Wondering if that
makes any difference...

Again I will let you know.

Thanks,

Mike

That's strange....Unless mabye its in the hostheader (or lack of) on the
webserver. Check what hostheader is in there.

Ace

 

[Mike Klick]

Ace:

I tested this again with someone helping me. We put back 'new'. The
performance was a little slower, but nothing like it was before. Remember
before it was very or extrememly slow. I think adding this record that
resolved to the same IP DOES affect performance. It is noticable. I thought
DNS was simply resolving the name. Why is page generation affected?

The web site is being hosted outside and on a Mac server. You want me to
find out if they have hostheaders?

Mike

"Ace Fekay [MVP]"

 

[Mike Klick]

Ace:

I talked to the hoster. They are using Virtual Hosting so yes they are using
host headers.

Is the problem with them?

Mike


"Ace Fekay [MVP]"

 

[Ace Fekay [MVP]]

In

Ace:

I talked to the hoster. They are using Virtual Hosting so yes they
are using host headers.

Is the problem with them?

Mike

It maybe the hostheader and the way their webserver is accepting the
connection. I cannot see how having multiple names for an IP affects this.
We do this all the time.

One way to test if it is your server is to use NetDIG to find out the
response time of a query. Run it for both records and look at the response
times. This will eliminate whether its your server or the hosting company's
webserver.

Netdig can be found at www.mvptools.com and is a free download written and
distributed by our own William Stacey, MVP. Additionally, you'll find his
posts in these newsgroups as well. Great tool.

Ace

 

[Mike Klick]

Ace:

I am not as familiar with DIG or Netdig but I have used www.dnsstuff.com I
ran the test on the site in question. IT FAILED EVERYTIME. Got an F.

(I am an ex-ISP admin and used it a bunch.)

I have written the hoster and told him what I found. He should get back to
me soon.

I will let you know. In the mean time - maybe a guy like me should not admit
it, but is there a guide somewhere that can help me understand Netdig's
output?

Mike

"Ace Fekay [MVP]"

 

[Mike Klick]

Ace:

I would like to repond off the newsgroup so I don't reveal the
organization's name.

Can I and how?

Mike

 

[Ace Fekay [MVP]]

In

Ace:

I would like to repond off the newsgroup so I don't reveal the
organization's name.

Can I and how?

Mike

My email is, as my posts properties indicate, is my
(e-mail address removed). Just substitute my actual firstname and
lastname with no periods, commas or anything else, @hotmail.com. Be glad to
help you out.


Ace

 

[Ace Fekay [MVP]]

In

Ace:

I am not as familiar with DIG or Netdig but I have used
www.dnsstuff.com I ran the test on the site in question. IT FAILED
EVERYTIME. Got an F.

(I am an ex-ISP admin and used it a bunch.)

I have written the hoster and told him what I found. He should get
back to me soon.

I will let you know. In the mean time - maybe a guy like me should
not admit it, but is there a guide somewhere that can help me
understand Netdig's output?

Mike

DNS Stuff gives you so much info. To find out more specific info, using
tools like Netdig will give that to you. Just run it, and choose a DNS
server, and choose the IP or name you want to check. In the beginning of the
output it gives you the response time the DNS server took to respond, among
all the other info it gives out.

Ace