Round Robin dns

Craig B

Trying to configure round robin dns for a web site. Have the technote
Configuring Round Robin but not quite following it.

I have made three A records with the same name and different IP's and add
the dword reg key for Roundrobin set at 1. Tracerouting shows it simply goes
the first one in the list over and over.

What have i missed? Using Windows 2003 SP2 on the dns machines using a
standard primary not ad integrated zone

thanks

Kevin D. Goodknecht Sr. [MVP]

Read inline please.

In news:,
Craig B <> typed:
> Trying to configure round robin dns for a web site. Have the technote
> Configuring Round Robin but not quite following it.
>
> I have made three A records with the same name and different IP's and
> add the dword reg key for Roundrobin set at 1. Tracerouting shows it
> simply goes the first one in the list over and over.
>
> What have i missed? Using Windows 2003 SP2 on the dns machines using
> a standard primary not ad integrated zone

Round robin rotates the order of the record on each consecutive DNS query,
this does not apply to cached records, cached queries are not rotated, when
the TTL on the cached record expires on the client, and the client queries
DNS again, the DNS server returns the records according to the rotation of
the records when last queried by any client.
You also have to consider the effect of Netmask ordering of the records if
Netmask ordering is enabled. Netmask ordering overrides Round Robin. DNS
will order the records by the closest match of the querying client, so if
you want the records rotated without regards of Netmask ordering, you need
to disable Netmask ordering.
Even with Netmask ordering disabled and round robin enabled, is no guarantee
the same client will get the records re-ordered on each consecutive query
because other clients querying that same name and caching of the records
affects the order of the records.
If you want to see round robin in action, you'll need stop the DNS Client
service
(net stop dnscache) and disable netmask ordering, but even this is affected
by other clients.



--
Best regards,
Kevin D. Goodknecht Sr. [MVP]
Hope This Helps

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Kevin D. Goodknecht Sr. [MVP]

Read inline please.

In news:,
Craig B <> typed:
> Trying to configure round robin dns for a web site. Have the technote
> Configuring Round Robin but not quite following it.
>
> I have made three A records with the same name and different IP's and
> add the dword reg key for Roundrobin set at 1. Tracerouting shows it
> simply goes the first one in the list over and over.
>
> What have i missed? Using Windows 2003 SP2 on the dns machines using
> a standard primary not ad integrated zone

Round robin rotates the order of the record on each consecutive DNS query,
this does not apply to cached records, cached queries are not rotated, when
the TTL on the cached record expires on the client, and the client queries
DNS again, the DNS server returns the records according to the rotation of
the records when last queried by any client.
You also have to consider the effect of Netmask ordering of the records if
Netmask ordering is enabled. Netmask ordering overrides Round Robin. DNS
will order the records by the closest match of the querying client, so if
you want the records rotated without regards of Netmask ordering, you need
to disable Netmask ordering.
Even with Netmask ordering disabled and round robin enabled, is no guarantee
the same client will get the records re-ordered on each consecutive query
because other clients querying that same name and caching of the records
affects the order of the records.
If you want to see round robin in action, you'll need stop the DNS Client
service
(net stop dnscache) and disable netmask ordering, but even this is affected
by other clients.



--
Best regards,
Kevin D. Goodknecht Sr. [MVP]
Hope This Helps

===================================
When responding to posts, please "Reply to Group"
via your newsreader so that others may learn and
benefit from your issue, to respond directly to
me remove the nospam. from my email address.
===================================



===================================
Use Outlook Express?... Get OE_Quotefix:
It will strip signature out and more

===================================
Keep a back up of your OE settings and folders
with OEBackup:

===================================