Re: Forwarders

From: sharad (sharadnaik_at_nospam-vsnl.net)
Date: 02/17/04 

Date: Tue, 17 Feb 2004 19:31:36 +0530

Thanks Rolland,

Uptill now I worked not more than 40 clients network,
however, I guessed that 200 people would not be much
load to DNS in normal situation, but it's mostly because
of the load of e-mails, I was not sure whether the DNS
will be overloaded or not.
The volume of e-mails roughly could be 12 to 15 thousand
mails /hour shared by two mail servers.
I am not worried abt ISP's DNS server down, never
had such problem yet with the new ISP since past
6 months. I thought if I use Root Hints, then number
of requests handled in a given time would be less
compared with use of forwarder.

Is a load of about 15000 requests per hour (roughly
4 reuests per second) an overload or it would be fine?
(Assuming the connection speed / hardware is no issue.)
(some email with attachment will reduce the load but then
add number of hits in IE, so total I assume will be the same
in an hour.)

Further you say RR has been supported since win2K,
do you mean Round Robin is supported?
The 'Enable Round Robin' option on the advanced
tab in DNS server properties I think is for returning
in round robin if there exist records for a host with
multiple IPs, and not for using the forwders in
round robin fashion.

I considered using ISP's one of DNS directly in one of
the mails server, but there also I am not sure since the
ISP's DNS will be handling other load too.

Sharad

"Roland Hall" <nobody@nowhere> wrote in message
news:u84%23SUV9DHA.2560@TK2MSFTNGP09.phx.gbl...
> "sharad" wrote:
> : My network is a Windows 2003 standard Edition, set up as AD, DHCP,
> : Mail Server (third party) and NAT, serving normally about 20 clients.
> : For external resolution I use forwarders and have given 3 DNS servers
> : of the ISP.
> : Next week, however, there is a conference and additional 200 PCs
> : will be hired and hooked to the server. The participants will not join
the
> : domain. I have set up a few PCs with lots of HDD's which contain the
> : required
> : data and the participants can access the shares on this PC.
> :
> : However for internet and e-mail , the traffic will go through the NAT,
> : (the addtional PCs will get IP from the DHCP)
> : and our email server will serve as SMTP server for them, and I guess
> : there will be a lot of mail and internet traffic, especially mail
traffic
> : since mails will be sent with number of different receipients (different
> : domains all over the world), in CC. So I added another Mail
> : server on the same server, and both listen to different IPs, that
> : part is working fine, half of the PCs using one mail server
> : the rest the other. Everyone will use their own pop server and
> : on all the computers, mail clients pop and smtp server will be
> : configured with their respective IP addresses and not host name
> : (to reduce that load on the DNS).
> :
> : Both SMTP server will run with 12 threads each so total 24 threads.
> : I am not sure but somehow feel that, this will cause lot of load on the
> : DNS during the conference (which will be for 4 days.), and there will
> : be considerable dealy.
> : As for forwarders, I can add more (have some friends which will
> : allow me to use their DNS as forwarders). However, though I am
> : not sure, I think that DNS does not use forwarders in round robin
> : fashion, since in the forwarders tab there is provision to move
> : a forwarder up or down. Am I correct on this or does DNS
> : use forwarders in round robin fashion? Or does it use always
> : the top one in the list and will go to next only if the first one is
down
> : not responding, times out?
> : If later is the case, is there a way to set to use the forwaders in
round
> : robin
> : fashion.
> : If not possible then I am thinking of setting conditional forwarding for
> : dirretnet roots , .com , .net .org etc. and where some domains are
> : know to me, will also set conditional forwarding for them.
> : Would like if any one has other suggestions.
>
> I doubt 200 clients are going to bring your DNS server to its knees. Your
> going to see more performance hits with mail than DNS.
>
> However, W2K3 comes with a new DNS feature; conditional forwarding.
> http://techrepublic.com.com/5100-6268-5112303.html
>
> RR has been supported since W2K but NLB is better but neither will tell
you
> if a service has crashed and they don't perform session state.
>
> If you're worried about a forwarder being down, then remove all
forwarders.
> This will cause the root hint servers to be used for public addressing.
> While performance is slightly better with [a] forwarder[s] to your ISP, it
> does bring a single point of failure which is not present when you do not
> use forwarders.
>
> How much more performance are you going to gain if an ISP DNS server goes
> down? Probably a good idea to test before next week with and without.
>
> HTH...
>
> --
> Roland Hall
> /* This information is distributed in the hope that it will be useful, but
> without any warranty; without even the implied warranty of merchantability
> or fitness for a particular purpose. */
> Online Support for IT Professionals -
> http://support.microsoft.com/servicedesks/technet/default.asp?fr=0&sd=tech
>
> --
> Roland Hall
> /* This information is distributed in the hope that it will be useful, but
> without any warranty; without even the implied warranty of merchantability
> or fitness for a particular purpose. */
> Online Support for IT Professionals -
> http://support.microsoft.com/servicedesks/technet/default.asp?fr=0&sd=tech
>
>
>

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