Amahi defaults to providing DNS forwarding through OpenDNS.

If you would like to change that to your router or your ISP or some other provider, follow the guidance below:

Amahi 7 or greater (Fedora)

Log in to your dashboard as your 1st admin user, the accomplish the following:

Verify Advanced Settings is enabled.
Select Network tab, then Settings.
Choose desired DNS provider:
- Preconfigured (Google Public DNS, OpenNIC DNS, or OpenDNS)
- Custom
  - Enter the IP addresses for the DNS provider.
  - Select Update DNS IPs

NOTE: You may need to renew the DHCP lease on your clients to use the new DNS provider.

Amahi 6 (Ubuntu 12.04.x)

This has to be done via command line. Issue this command, provided you have two IP addresses of the providers:

hda-change-dns FIRST_DNS_IP SECOND_DNS_IP

For instance, if you would like to use Google's Public DNS service, you would do:

hda-change-dns 8.8.8.8 8.8.4.4

To revert back to the default OpenDNS settings use:

hda-change-dns 208.67.222.222 208.67.220.220

In some cases you may need to use the full path for hda-change-dns

example: /usr/bin/hda-change-dns 208.67.222.222 208.67.220.220

Fedora

Clear out DNS cache, do the following as root user:

nscd -i hosts

Ubuntu

sudo /etc/init.d/dns-clean