DNS servers for Router DHCP scopes

[Neri Gary Cacatian]

Hi,

Just want to verify. For a dhcp scope, you can define max 8 dns server entries. Im wondering how will it be assigned to a host, if a host (i.e. windows users)  can only use 2 dns servers at a time.

Thanks in advance

[Georg Pauwen]

Hello,

your clients will take the first two, in order. I don't think there is a sanity check when you have more than two DNS servers configured, and the first or the second are not reachable.

Good practice to always use 8.8.8.8 and 8.8.4.4, they are supposed to never go down...

[Neri Gary Cacatian]

Hi,

Thanks for the feedback. i was just wondering why they put a max of 8 if you could only use 2.

[Georg Pauwen]

I know that UNIX/LINUX can have three DNS servers, not sure about all the other OSs out there, but the reason might be compatibility with clients other than Windows clients...

[paul driver]

Hello

FYI - you can configure multiple dns server in windows, you just have to go to the advanced properties of the network adapter to do it.

Also the windows client will query itself first for name resolution and if not successful will then sequentially query each dns server specified in its adapter for successful name resolution.

res

Paul

[Neri Gary Cacatian]

is it also possible for dhcp? I believe its only possible via static as an alternative configuration

[sbhadrav@cisco.com]

If you want the router to assign dns to clients you need this config

ip dhcp pool vlan10
 network 10.20.90.0 255.255.255.0
 default-router 10.20.90.1
 dns-server 8.8.8.8.