DNS

[Madhu Sudhan_1]

How does load balancing of web sites work if a particular domain called www.itplindia.com have two ip addresses.
1)Internet name servers allow this kind of facility ?

If so,

2)How does the resolution happen in this case ?

Thanks,

[Lasse Knudsen · Accepted solution]

Normally this is what happens:

In this example assume that the web-server has to 'A' records in DNS (eg. 10.0.0.1 and 10.0.0.2).

The DNS server returns *both* addresses. 50% of the times the .1 address is listed first and 50% the .2 address is listed first.

This is what is called round-robin.

All Bind implementations behave like this unless the DNS-admin specify a specific 'sortlist'.

[Albert E. Whale, CISSP]

Madhu,

The web server can have multiple NICs or IP Aliases associated with it. DNS will attempt two things:

1. To provide the address which matches the network of the requester (or some reasonable approximate answer closest to the IP Address of the requestor).

2. DNS will also attempt to 'alternate' between the two interfaces if they are on the same network, or if the network of the requestor does not match one of the answers.

Hope that helps!

Happy Thanksgiving!

[Madhu Sudhan_1]

Thanks. You guys are smart.

Happy thanks giving.

...Madhu